ST AN3955 APPLICATION NOTE

AN3955

Application note

CR95HF library for ISO/IEC 14443-3 and SRIX contactless tag ICs

1 Introduction

This document describes the ISO/IEC 14443-3 libraries used by a microcontroller to drive the CR95HF 13.56 MHz multiprotocol contactless transceiver using an SPI or UART interface in order to perform wireless communications with ISO/IEC 14443 Type A or B contactless tag.

The library was developed to speed up the development of applications using the CR95HF.

The CR95HF library is composed of three layers:

■CR95HF low level layer

■Standard ISO/IEC 14443-3 protocol layer (type A and type B)

■SRIX4K product specific layer

The library code has been developed in ANSI C language, and validated on an STM32 evaluation board.

1.1Reference documents

■CR95HF datasheet

■ISO/IEC 14443-3 specification

■SRIX4K datasheet

September 2011

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www.st.com

Contents	AN3955

Contents

1	Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 1
	1.1	Reference documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1
2	Acronyms and notational conventions . . . . . . . . . . . . . . . . . . . . . . . . . .		9
	2.1	List of terms and acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
	2.2	Notational conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	10

2.2.1 Binary number representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.2 Hexadecimal number representation . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.3 Decimal number representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3	Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		11
	3.1	CR95HF overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	3.2	ISO/IEC 14443-3 overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	3.3	SRIX4K product overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	3.4	Library overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12

4	CR95HF low level layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		13
	4.1	Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	13
	4.2	Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	13
	4.3	CR95HF layer functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	14
	4.4	IDN function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	16
	4.5	ECHO function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	16
	4.6	ProtocolSelect function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	16
	4.7	SendRecv function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	18
	4.8	Idle function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	21
	4.9	RdReg function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	21
	4.10	BaudRate function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	21
	4.11	SendEOF function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	22
	4.12	FieldOff function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	22
	4.13	HexCommandToStringCommand function . . . . . . . . . . . . . . . . . . . . . . . .	22
	4.14	IsReaderResultCodeOk function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	23
	4.15	IsReaderErrorCode function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	23

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4.16 IsCommandExists function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4.17 GetReaderErrorCode function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.18 Application example: protocol selection and communication . . . . . . . . . . 25

5	ISO/IEC 14443-3 layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			26
	5.1	ISO/IEC 14443-3 Type A layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		26
		5.1.1	ISO/IEC 14443-3 Type A command format . . . . . . . . . . . . . . . . . . . . . .	26
		5.1.2	EOF and SOF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
		5.1.3	Parity bit management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	27
		5.1.4	ISO/IEC 14443-3 Type A CRC16 management . . . . . . . . . . . . . . . . . . .	27
		5.1.5	Functions of ISO/IEC 14443_A layer . . . . . . . . . . . . . . . . . . . . . . . . . . .	28
		5.1.6	CR95HF configuration function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	30
		5.1.7	ISO/IEC 14443-3 Type A command function . . . . . . . . . . . . . . . . . . . . .	30
		5.1.8	ISO/IEC 14443-3 Type A Split function . . . . . . . . . . . . . . . . . . . . . . . . .	33
		5.1.9	ISO/IEC 14443-3 Type A Is function . . . . . . . . . . . . . . . . . . . . . . . . . . .	34
		5.1.10	ISO/IEC 14443-3 Type A GET functions . . . . . . . . . . . . . . . . . . . . . . . .	36
		5.1.11	ISO/IEC 14443-3 Type A Advanced functions . . . . . . . . . . . . . . . . . . . .	37
	5.2	ISO/IEC 14443-3 Type B layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		40
		5.2.1	ISO/IEC 14443-3 Type B command format . . . . . . . . . . . . . . . . . . . . . .	40
		5.2.2	EOF and SOF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	40
		5.2.3	Data management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	40
		5.2.4	ISO/IEC 14443-3 Type B CRC16 management . . . . . . . . . . . . . . . . . . .	40
		5.2.5	Functions of ISO/IEC 14443-3 Type B layer . . . . . . . . . . . . . . . . . . . . .	40
		5.2.6	CR95HF configuration function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	42
		5.2.7	ISO/IEC 14443-3 Type B Set function . . . . . . . . . . . . . . . . . . . . . . . . . .	42
		5.2.8	ISO/IEC 14443-3 Type B command function . . . . . . . . . . . . . . . . . . . . .	43
		5.2.9	ISO/IEC 14443-3 Type B Split function . . . . . . . . . . . . . . . . . . . . . . . . .	45
		5.2.10	ISO/IEC 14443-3 Type B Is function . . . . . . . . . . . . . . . . . . . . . . . . . . .	47

6	SRIX4K library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	48
	6.1 SRIX4K command format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	48

6.1.1 SRIX4K CR16 management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 6.1.2 Functions of SRIX4K layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 6.1.3 CR95HF configuration function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 6.1.4 SRIX4K command function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 6.1.5 SRIX4K Split functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 6.1.6 SRIX4K Is function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

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		6.1.7	SRIX4K Advanced function . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . 59
7	Project example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			. . . 60
	7.1	Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . 60
	7.2	Keil µvision® . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . 60
	7.3	Project structure on Keil µvision® . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . 61

7.3.1 Standard peripheral drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 7.3.2 Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 7.3.3 Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

	7.4	Application functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		62
		7.4.1	Application example flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	63
		7.4.2	Detect an ISO/IEC 14443-3 Type A tag function . . . . . . . . . . . . . . . . . .	64
		7.4.3	Detect an ISO/IEC 14443-3 Type B tag function . . . . . . . . . . . . . . . . . .	65
		7.4.4	Detect an SRIX tag function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	65
8	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			67

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List of figures

Figure 1. Typical application block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 2. Interaction between typical user application and CR95HF library layers . . . . . . . . . . . . . . 12 Figure 3. Example of function flowchart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Figure 4. Select sequence algorithm flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Figure 5. Example of project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Figure 6. Flowchart of application example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Figure 7. Flowchart of User detects an ISO/IEC 14443-3 Type A tag . . . . . . . . . . . . . . . . . . . . . . . . 64 Figure 8. Flowchart of User detects an ISO/IEC 14443-3 Type B tag . . . . . . . . . . . . . . . . . . . . . . . . 65 Figure 9. SRIX tag detection flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

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List of tables	AN3955

List of tables

Table 1. Terms and acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Table 2. CR95HF layer functions based on CR95HF commands . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 3. CR95HF layer additional functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 4. CR95HF_IDN function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 5. CR95HF_Echo function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 6. CR95HF_ProtocolSelect function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 7. CR95HF_ProtocolSelect ISO/IEC 14443-3 Type A protocol parameter. . . . . . . . . . . . . . . 17 Table 8. CR95HF_ProtocolSelect ISO14443-3 Type B protocol parameter. . . . . . . . . . . . . . . . . . . 17 Table 9. CR95HF_SendRecv function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 10. SendRecv command in ISO/IEC 14443-3 Type A case . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 11. SendRecv command in ISO/IEC 14443-3 Type B case . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Table 12. CR95HF success response value for ISO/IEC 14443-3 Type A. . . . . . . . . . . . . . . . . . . . . 19 Table 13. Specific success code for ACK or NAK contactless response . . . . . . . . . . . . . . . . . . . . . . 20 Table 14. CR95HF success response value for ISO/IEC 14443-3 Type B. . . . . . . . . . . . . . . . . . . . . 20 Table 15. CR95HF error response value for ISO/IEC 14443-3 Type A and B . . . . . . . . . . . . . . . . . . 20 Table 16. CR95HF_Idle function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Table 17. CR95HF_RdReg function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Table 18. CR95HF_BaudRate function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Table 19. CR95HF_SendEOF function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Table 20. CR95HF_FieldOff function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Table 21. CR95HF_HexCommandToStringCommand function description. . . . . . . . . . . . . . . . . . . . 22 Table 22. CR95HF_IsReaderResultCodeOk function description . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 23. CR95HF_IsReaderErrorCode function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 24. CR95HF_IsCommandExists function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 25. CR95HF_GetReaderErrorCode function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Table 26. ISO/IEC 14443-3 Type A commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Table 27. Configuration of the CR95HF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Table 28. ISO/IEC 14443-3 Type A layer function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Table 29. ISO14443A_ProtocolSelect function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Table 30. ISO/IEC 14443-3 Type A Is function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Table 31. ISO/IEC 14443-3 Type A GET function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Table 32. ISO/IEC 14443-3 Type A Advanced function description . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Table 33. ISO14443A_ProtocolSelect function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Table 34. ISO14443A_REQA function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Table 35. ISO14443A_WUPA function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Table 36. ISO14443A_HLTA function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Table 37. ISO14443A_AnticollisionLevel1 function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Table 38. ISO14443A_AnticollisionLevel2 function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Table 39. ISO14443A_AnticollisionLevel3 function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Table 40. ISO14443A_SelectLevel1 function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Table 41. ISO14443A_SelectLevel2 functiond description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Table 42. ISO14443A_SelectLevel3 function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Table 43. ISO14443A_Split ATQA function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Table 44. ISO14443A_IsCollisionDetected function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Table 45. ISO14443A_IsCRCError function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Table 46. ISO14443A_IsParityError function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Table 47. ISO14443A_Is14443_4Compatible function description . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Table 48. ISO14443A_IsUIDComplete function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

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Table 49. ISO14443A_IsPresent function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Table 50. ISO14443A_IsCorrectBCC function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Table 51. ISO14443A_GetSignificantBit function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Table 52. ISO14443A_GetFirstCollisionByte function description . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Table 53. ISO14443A_GetFirstCollisionBit function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Table 54. ISO14443A_SelectSequence function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Table 55. ISO14443A_GetUIDsize function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Table 56. ISO14443A_GetUID function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Table 57. ISO/IEC14443-3 Type B configuration function description . . . . . . . . . . . . . . . . . . . . . . . . 40 Table 58. ISO14443B_SetParamByte function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 59. ISO/IEC 14443-3 Type B command functions description . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 60. ISO/IEC 14443-3 Type B Split functions description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 61. ISO/IEC 14443-3 Type B Is function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 62. ISO14443B_ProtocolSelect function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Table 63. ISO14443B_SetParamByte function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Table 64. ISO14443B_REQB function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Table 65. ISO14443B_WUPB function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Table 66. ISO14443B_SlotMarker function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Table 67. ISO14443B_Attrib function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Table 68. ISO14443B_HLTB function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Table 69. ISO14443B_SplitATQB function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Table 70. ISO14443B_SplitApplicationDataField function description . . . . . . . . . . . . . . . . . . . . . . . . 45 Table 71. ISO14443B_SplitProtocolInfoField function description . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Table 72. ISO14443B_IsPresent function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Table 73. SRIX4K_ProtocolSelect function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Table 74. Commands included in the lib_SRIX4k.c file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Table 75. SRIX4K Split functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 76. SRIX4K_Is functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 77. SRIX4K_Advanced functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 78. SRIX4K_ProtocolSelect function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Table 79. SRIX4K_Initiate function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Table 80. SRIX4K_Pcall16 function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Table 81. SRIX4K_SlotMarker function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Table 82. SRIX4K_SelectChipID command description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Table 83. SRIX4K_Completion function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Table 84. SRIX4K_ResetToInventory command description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Table 85. SRIX4K_ReadSingleBlock function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Table 86. SRIX4K_WriteSingleBlock function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Table 87. SRIX4K_GetUID function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Table 88. SRIX4K_SplitInitiateResponse function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Table 89. SRIX4K_SplitPCall16Response function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Table 90. SRIX4K_SplitSlotMarkerResponse function description. . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Table 91. SRIX4K_SplitSelectChipIDResponse function description . . . . . . . . . . . . . . . . . . . . . . . . . 55 Table 92. SRIX4K_SplitCompletionResponse function description . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Table 93. SRIX4K_SplitReadSingleBlockResponse function description. . . . . . . . . . . . . . . . . . . . . . 56 Table 94. SRIX4K_SplitWritedBlockResponse function description. . . . . . . . . . . . . . . . . . . . . . . . . . 57 Table 95. SRIX4K_SplitGetUIDResponse function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Table 96. SRIX4K_IsPresent function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Table 97. SRIX4K_IsSRIX4KPresent function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Table 98. SRIX4K_GetUIDadvanced function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Table 99. SRIX4K_GetChipIDAndSelectIt function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Table 100. SRIX4K_Anticollision function description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

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List of tables	AN3955

Table 101. Detection of an ISO/IEC 14443-3 Type A contactless tag . . . . . . . . . . . . . . . . . . . . . . . . . 64 Table 102. Detection of an SRIX tag function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Table 103. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

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AN3955	Acronyms and notational conventions

2 Acronyms and notational conventions

2.1List of terms and acronyms

Table 1.	Terms and acronyms
	Terms	Definition
AFI		Application Family Identifier
ATQA		Answer to Request Type A
ATQB		Answer to Request Type B
ATS		Answer To Select
CRC		Cyclic Redundancy Check
EOF		End Of Frame
FWT		Frame Waiting Time
HLTA		Halt command Type A
HLTB		Halt command Type B
IC		Integrated Circuit
IEC		International Electrotechnical Commission
ISO		International Organization for Standardization
MCU		Microcontroller Unit
NACK		Negative Acknowledge
NFC		Near Field Communication
RATS		Request for Answer To Select
REQA		Request command Type A
REQB		Request command Type B
RF		Radio Frequency
RFID		Radio Frequency Identification
RFU		Reserved for Future Use
SAK		Select AcKnowledge
SOF		Start Of Frame
SRI		Short Range Interface
SRIX		Short Range Interface with anti clone function
UID		Unique Identifier
WUPA		Wake-Up A command Type A
WUPB		Wake-Up A command Type B
XOR		eXclusif OR

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2.2Notational conventions

The following conventions and notations apply in this document unless otherwise stated.

2.2.1Binary number representation

Binary numbers are represented by strings of digits 0 and 1 shown with the Most Significant Bit (MSB) on the left, the Least Signifcant Bit (LSB) on the right, and “0b” added at the beginning.

For example: 0b11110101

2.2.2Hexadecimal number representation

Hexadecimal numbers are represented by using the numbers 0 to 9, the characters A - F, and a “0x” added at the beginning. The Most Significant Byte (MSB) is shown on the left and the Least Significant Byte (LSB) on the right.

For example: 0xF5

2.2.3Decimal number representation

Decimal numbers are represented as is, without any trailing character.

For example: 245

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3 Overview

3.1CR95HF overview

The CR95HF is a Radio Frenquency (RF) transceiver Integrated Circuit (IC) for 13.56 MHz contactless tags, which includes ISO/IEC 14443, ISO/IEC 15693 and ISO/IEC 18092 protocols. It manages the RF communication with Radio Frequency Identification (RFID) or Near Field Communication (NFC) tags. It includes trame coding, RF modulation and contactless tag response decoding.

The CR95HF is a slave device and must be controlled by a host (Microcontroller Unit). This library is an interface between user application function and standard peripheral driver.

The library was written in compliance with ANSI C standards.

Figure 1 describes a typical application block diagram.

Figure 1. Typical application block diagram

							Contactless tag
CR95HF							14443 type A
library
					CR95HF	13,56 MHz RF commands	Or
MCU
							14443 type B
							AI18873a

For more details concerning the CR95HF, please refer to CR95HF datasheet.

3.2ISO/IEC 14443-3 overview

The ISO/IEC 14443-3 is a standard, which specifies two different RF protocols (Type A and Type B). It describes low-level functions allowing to handle one ore more contactless tags. As an example, the ISO/IEC 14443-3 commands can be used to read the Unique Identifier (UID) or to perform anti-collision.

The higher level commands to read or write the user memory of contactless tags are not described in ISO/IEC 14443-3 specifications. These commands are defined in the contactless datasheet. For instance, the SRIX4K datasheet defines Read, Write and other specific commands.

For more information about Read, Write or other commands, refer to the SRIX4K datasheet.

Since the frames coding specified by ISO/IEC 14443 Type A differ from Type B, the CR95HF cannot communicate with an ISO/IEC 14443 Type A and an ISO/IEC 14443 Type B contactless tag at the same time.

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3.3SRIX4K product overview

The SRIX4K is an STMicroelectronics contactless tag powered by an RF field. It contains a 4-kbit EEPROM memory that can be accessed by using RF commands.

For more information about low-level commands to handle a tag and an upper level to read, write or lock memory, refer to the SRIX4K datasheeet.

SRIX4K is compliant with ISO/IEC 14443-3 Type B frame format specification.

3.4Library overview

The library described in this application note is composed of three layers:

●A low-level layer supporting the commands described in the CR95HF datasheet. This level is fully supported by the CR95HF library.

●An intermediate layer based on the ISO/IEC 14443-3 protocol. This layer is divided in two files, one for Type A and another for Type B.

●An upper layer supporting the commands described in the SRIX4K datasheet.

The library can be downloaded from STMicroelectronics internet site at http://www.st.com.

Figure 2 shows an example of application architecture and describes the interaction between a typical user application and the CR95HF library layers.

Figure 2. Interaction between typical user application and CR95HF library layers

User functions (user application specific)

Product layer (embeds commands defined in the product datasheet)

SRiX4K layer

Protocol layer (embeds commands defined in the ISO/IEC 14443-3 specification)

ISO14443_3 type A library layer		ISO14443_3 type B library layer

CR95HF library layer

(integrates the commands defined in CR95HF datasheet)

CR95HF library

Standard peripheral driver (MCU specific layer)

MS19951V1

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4 CR95HF low level layer

For a brief description of CR95HF, refer to Section 3.1: CR95HF overview.

This layer is composed of:

●the lib_CR95HF.c source file

●the lib_CR95HF.h include file

4.1Types

The CR95HF library functions use the following ANSI C compliant types:

typedef	unsigned char	uint8_t;
typedef	signed char	int8_t;
typedef	const uint8_t	uc8;
typedef	signed short int	int16_t;

4.2Definition

The layer supports all the commands defined in the CR95HF datasheet. Each CR95HF command corresponds to a specific function. As an example, the function calling the ECHO command is int8_t CR95HF_Echo (uint8_t *pResponse).

Additional functions are described in Table 3: CR95HF layer additional functions.

Application developers can use the functions described in Table 2: CR95HF layer functions based on CR95HF commands to create their own higher level functions.

For more details about commands, refer to the CR95HF datasheet.

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4.3CR95HF layer functions

The tables below introduce the functions available in the CR95HF layer.

	.	CR95HF layer functions based on CR95HF commands
	Table 2.
	Function name		Brief description
			Sends an IDN command to CR95HF device. It returns its version
	CR95HF_IDN		number. For more details about CR95HF_IDN function, refer to
			Section 4.4: IDN function.
			Sends an Echo command to CR95HF device which returns an Echo
	CR95HF_Echo		response. The Echo function checks if communications can be
			started between the MCU and the CR95HF. For more details about
			CR95HF_Echo function, refer to Section 4.5: ECHO function.
			Sends a ProtocolSelect command to CR95HF device. It selects the
	CR95HF_ProtocolSelect		RF communication protocol, configures RF parameters and switches
			the RF field on. For more details about CR95HF_ProtocolSelect
			function, refer to Section 4.6: ProtocolSelect function.
			Sends a SendRecv command. The parameter sent to the command
			is the frame which is coded according to the protocol previously
	CR95HF_SendRecv		selected by issuing a ProtocolSelect command. For more details
			about CR95HF_SendRecv function, refer to Section 4.7: SendRecv
			function.
			Sends an Idle command to the CR95HF device to switch it into low
	CR95HF_Idle		consumption mode. For more details about CR95HF_Idle function,
			refer to Section 4.8: Idle function.
			Sends a ReadRegister command to the CR95HF device to read the
	CR95HF_RdReg		CR95HF internal register. For more details about CR95HF_RdReg
			function, refer to Section 4.9: RdReg function.
			Sends a Baudrate command to the CR95HF device. It changes the
	CR95HF_BaudRate		CR95HF UART baudrate. For more details about
			CR95HF_BaudRatefunction, refer to Section 4.10: BaudRate
			function.

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.		CR95HF layer additional functions
	Table 3.
		Function name	Brief description
			Sends an RF pulse (EOF). For more details about
	CR95HF_SendEOF		CR95HF_SendEOF function, refer to Section 4.11:
			SendEOF function.
			Switches off the RF field. For more details about
	CR95HF_FieldOff		CR95HF_FieldOff function, refer to Section 4.12:
			FieldOff function.
			Translates hexadecimal command code to command
			name. It returns the ASCII code of the command. For
	CR95HF_HexCommandToStringCommand		more details about
			CR95HF_HexCommandToStringCommand function,
			refer to Section 4.13: HexCommandToStringCommand
			function.
			Translates hexadecimal error code to error code
			description. It returns a description of the error
	CR95HF_GetReaderErrorCode		contained in the ReaderReply parameter. For more
			details about CR95HF_GetReaderErrorCode, refer
			to Section 4.17: GetReaderErrorCode function.
			Checks if returned code is a successful code. It returns
			CR95HF_SUCCESS_CODE if the CR95HF command is
	CR95HF_IsReaderResultCodeOk		successful. For more details about
			CR95HF_IsReaderResultCodeOk function, refer to
			Section 4.14: IsReaderResultCodeOk function.
			Checks if returned code is an error code. It returns
			CR95HF_SUCCESS_CODE value if the CR95HF
	CR95HF_IsReaderErrorCode		command has returned an error code. For more details
			about CR95HF_IsReaderErrorCode function, refer
			to Section 4.15: IsReaderErrorCode function.
			Checks if command is available. It returns
			CR95HF_SUCCESS_CODE if the CmdCode value
	CR95HF_IsCommandExists		exists. For more details about
			CR95HF_IsCommandExists function, refer to
			Section 4.16: IsCommandExists function.

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4.4IDN function

The CR95HF_IDN function sends an IDN command to the CR95HF device.

Table 4.	CR95HF_IDN function description
Prototype		result = int8_t CR95HF_IDN (uint8_t *pResponse)
Input parameter		None
Output parameter		pResponse: Pointer to CR95HF response
Return parameter		CR95HF_SUCCESS_CODE: Function is successful.

4.5ECHO function

The CR95HF_Echo function sends an ECHO command to the CR95HF device.

Table 5.	CR95HF_Echo function description
Prototype		result = int8_t CR95HF_Echo (uint8_t *pResponse)
Input parameter		None
Output parameter		pResponse: Pointer to CR95HF response
Return parameter		CR95HF_SUCCESS_CODE: Function is successful.

4.6ProtocolSelect function

The CR95HF_ProtocolSelect function sends a ProtocolSelect command to the CR95HF device.

To set up communications with a contactless tag, the ProtocolSelect command must be sent to the CR95HF before the SendRecv commands.

	Table 6.	CR95HF_ProtocolSelect function description
	Prototype		result = int8_t CR95HF_ProtocolSelect(uc8
			Length,uc8 Protocol,uc8 *Data,uint8_t *pResponse)
			Length: Number of data bytes
	Input parameter		Protocol: Type of protocol(1)
			Data input: Pointer to data
	Output parameter		pResponse: Pointer to CR95HF response
			CR95HF_ERRORCODE_PARAMETER: Function failed
	Return parameter		CR95HF_SUCCESS_CODE: Function is successful.
			CR95HF_ERRORCODE_PARAMETERLENGTH: Parameter length is
			incorrect.

1. ISO/IEC 15693, ISO/IEC 18092, ISO/IEC 14443-3 Type A or Type B RF protocols.

The Data input parameter depends on the selected protocol. This application note applies to ISO/IEC 14443-3 Type A and ISO/IEC 14443-3 Type B products.

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Table 7 describes the ProtocolSelect command in ISO/IEC 14443-3 Type A case.

Table 7.	CR95HF_ProtocolSelect ISO/IEC 14443-3 Type A protocol parameter
Parameter name		Byte	Bit	Value	Example
Command Code		0	7:0	0x02	0x02020200
					ISO/IEC 14443-3 Type
Length		1	7:0	0x02
					A with reception and
Protocol		2	7:0	0x02: ISO/IEC 14443-3 Type A	transmission data
				protocol	rates at 106 kbps
		3	7:6	Transmission data rate
			5:4	Reception data rate
Parameter			3:0	RFU
		5:4	7:0	FWT= (256*16/fc)*(2*PP)*(MM+1)(1) (2)
				where “PP” represents byte 4 and “MM”
				byte 5.

1.Optional. If not specify default FWT~86 µs

2.PP <= 0x0E and 0x01 <= MM <= 0xFE

Table 8 describes the ProtocolSelect command in ISO/IEC 14443-3 Type B case.

Table 8.	CR95HF_ProtocolSelect ISO14443-3 Type B protocol parameter
Parameter name		Byte	Bit	Value	Example
Command Code		0	7:0	0x02	0x02020301
					ISO/IEC 14443-3 Type
Length		1	7:0	0x02
					B with reception and
Protocol		2	7:0	0x03: ISO/IEC 14443-3 Type B protocol	transmission data
					rates at 106 kbps
		3	7:6	Transmission data rate
			5:4	Reception data rate
			3:0	RFU	The CR95HF
				Append CRC
Parameter			0		manages the CRC.
				1: CR95HF appends CRC
				0: CR95HF does not append CRC
		5:4	7:0	FWT= (256*16/fc)*(2*PP)*(MM+1)(1) (2)
				where “PP” represents byte 4 and “MM”
				byte 5.

1.Optional. If not specify default FWT~300µs.

2.PP <= 0x0E and 0x01 <= MM <= 0xFE

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4.7SendRecv function

The CR95HF_SendRecv function sends a SendRecv command. The CR95HF encodes the frame, transmits it at 13.56 MHz, and decodes the contactless tag response.

The contactless tag response is then sent back in the pResponse parameter.

	Table 9.	CR95HF_SendRecv function description
	Prototype		result = int8_t CR95HF_SendRecv (uc8
			Length,uc8 *Parameters,uint8_t *pResponse)
	Input parameter		Length: Number of bytes in Parameters input
			Parameters input: Pointer to data
	Output parameter		pResponse : Pointer to CR95HF response
			CR95HF_ERRORCODE_PARAMETER: Function failed
	Return parameter		CR95HF_SUCCESS_CODE: Function is successful.
			CR95HF_ERRORCODE_PARAMETERLENGTH: Parameter
			length is incorrect.

The Parameters input depends on the selected protocol. This application note applies to ISO/IEC 14443-3 Type A and ISO/IEC 14443-3 Type B products.

Table 10 describes the SendRecv command in ISO/IEC 14443-3 Type A case.

Table 10. SendRecv command in ISO/IEC 14443-3 Type A case

	Parameter name	Byte	Bit	Value	Comments	Example
	Command Code	0	7:0	0x04	-	REQA command:
						0x04022607 with
		1	7:0	0xXX	Number of Data
	Length				bytes and	26: Data (REQA
						command code)
					transmission flag
						07: number
	Data	2:X	7:0	0xXX	Data
						of significant bits
						(REQA is coded on 7
		X+1	7	-	RFU
						bits)
			6	0b0	Split frame
			5	1: CR95HF
				appends CRC
	Transmission flag			0: CR95HF	Append CRC
				does not
				append CRC
			4	0b0	RFU
			3:0	0xX	Number of
					significant bits

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Table 11 describes the SendRecv command in ISO/IEC 14443-3 Type B case.

Table 11. SendRecv command in ISO/IEC 14443-3 Type B case

	Parameter name	Byte	Bit	Value	Comments	Example
	Command Code	0	7:0	0x04	-	REQB command:
						0x040305000
	Length	1	7:0	0xXX	Length of entire
					data
	Data	2:X	7:0	0xXX	Data

For more information, refer to CR95HF datasheet.Table 12 describes the CR95HF success response value for ISO/IEC 14443-3 Type A.

Table 12. CR95HF success response value for ISO/IEC 14443-3 Type A

Parameter	Byte Bit	Value	Comments	Example
name

Result	0	7:0	0x04	Success code	0X80054400280000
Code					where:
					80: success
Length	1	7:0	0xXX	Number of bytes of Data
				+ control bytes	05: Number of bytes
					4400: ATQA
Data	2:X	7:0	0xXX	Contactless tag response
					28: CRC error(1) &
			1: CR95HF has
	X+1	7		Collision between two	Number of significant
			detected a collision	contactless tag	bits: 8
			0: No collision detected	responses	00 00: No collision
					detected
		6	0	RFU
		5	1: CRC error	CRC error on contactless
			0: No CRC error	response
		4	1: Parity error	Parity error on
Control			0: No Parity error	contactless response
bytes
		3:0		Number of significant bits
				in the first byte(2)
	X+2	7:0	0xXX	Index of the first byte
				where the collision is
				detected(3)
	X+3	7:4	0b000	RFU
		3:0	0bXXXX	Index of the first bit where
				the collision is detected

1.CRC error bit is set but there is no CRC on ATQA response. So this bit is not significant.

2.Since the ISO/IEC 14443-3 Type A is a bit-oriented protocol, CR95HF can receive a non integer amount of bytes.

3.To calculate the point of collision between two contactless tag responses, the user application must refer to the control bytes. The byte where the collision is detected is indicated by Control Byte X+2 (Index of first byte), and the specific bit in the byte where the collision is detected is indicated by Control Byte X+3 (Index of first bit). Both indices start from 0 and the bit index can be 8, meaning that the collision affected parity. This information is only valid if the Collision Dectected bit (Bit 7 of control Byte X+1) is set.

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CR95HF low level layer	AN3955

CR95HF returns a specific correct code for ACK or NAK contactless response, coded on 4 bits, as described in Table 13.

Table 13. Specific success code for ACK or NAK contactless response

Parameter name	Byte	Bit	Value	Comments
Result Code	0	7:0	0x90	Success code
Length	1	7:0	0x04	Number of valid bits: 4
	2:X	7:0	0x01: NAK
Data			0x05: NAK	Contactless tag response
			0x0A: ACK

Table 14 describes the CR95HF success response value for ISO/IEC 14443-3 Type B.

Table 14. CR95HF success response value for ISO/IEC 14443-3 Type B

	Parameter	Byte Bit	Value	Comments	Example
	name

	Result Code 0		7:0	0x80	Success code	0x800F50AA0B000500
						000000B371716A2100
	Length	1	7:0	0xXX	Number of bytes of
						where:
					Data + control bytes
						80: Success
		2:X	7:0	0xXX	Contactless tag
	Data					0F: Number of byte
					response	50AA0B000500000000
		X+1	7:2	0b0000	RFU	B371716A21: ATQB
						00: CRC Ok
	Control		1	1: CRC error	CRC error or
				0: no CRC error	contactless
	bytes
					response
			0	-	RFU

For more information, refer to CR95HF datasheet.

If CR95HF_SendRecv function fails, the CR95HF returns an error code in the pResponse parameter (see Table 15). As an example, if no contactless tag is present in the RF field, the CR95HF response is 0x8700.

Table 15. CR95HF error response value for ISO/IEC 14443-3 Type A and B

Parameter name	Byte	Bit	Value	Example
Result code	0	7:0	0x08	0x8700: no contactless
Length	1	7:0	0x00	tag in the field

For more information about CR95HF error code, refer to CR95HF datasheet.

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4.8Idle function

This function sends an Idle command to the CR95HF to switch the CR95HF device into low consumption mode. Table 16 describes the CR95HF_Idle function.

Table 16. CR95HF_Idle function description

	Prototype	result = int8_t CR95HF_Idle(uc8
		Length,uc8 *Data,uint8_t *pResponse);
	Input parameter	Length: Number of data bytes
		Data: Pointer to data
	Output parameter	pResponse : Pointer to the CR95HF response
		CR95HF_ERRORCODE_PARAMETER: Function failed
	Return parameter	CR95HF_SUCCESS_CODE: Function is successful.
		CR95HF_ERRORCODE_PARAMETERLENGTH:
		Parameter length is incorrect.

4.9RdReg function

This function sends an RdReg command to the CR95HF in order to read the CR95HF internal register. Table 17 describes the CR95HF_RdReg function.

Table 17. CR95HF_RdReg function description

		result = int8_t CR95HF_RdReg(uc8
	Prototype	Length,uc8 Address,uc8 RegCount,uc8
		Flags,uint8_t *pResponse);
		Length : Number of bytes (Address+RegCount+Flags)
	Input parameter	Address: Register address
		RegCount: Number of bytes to read
		Flags: ST reserved (must be 0x00)
	Output parameter	pResponse : Pointer to CR95HF response
	Return parameter	CR95HF_SUCCESS_CODE: Function is successful.

4.10BaudRate function

This function sends a BaudRate command to the CR95HF. It allows configuring the UART baudrate. Table 18 describes the CR95HF_BaudRate function.

Table 18. CR95HF_BaudRate function description

	Prototype	result = int8_t CR95HF_BaudRate (uc8
		BaudRate,uint8_t *pResponse);
	Input parameter	BaudRate: New baud rate = 13.56/(2*BaudRate+2) Mbps
	Output parameter	pResponse : Pointer to the CR95HF response
	Return parameter	CR95HF_SUCCESS_CODE: Function is successful.

For more information about this command, please refer to CR95HF datasheet.

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