ST AN2500 Application note

AN2500

Application note

ST10 electric motor control library:

SPI drivers for MP49 power board

Introduction

STMicroelectronics provides a library of motor control functions that can be used as base blocks for motor control applications.

This application note describes the set of API to simplify the usage of the MP49 motor control power board. It provides ST10 compatible SPI drivers to configure the board and for diagnostic purposes.

March 2007

Rev 1

1/18

www.st.com

Contents	AN2500

Contents

1	Functions set overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
2	MP49 to CPU board communication overview . . . . . . . . . . . . . . . . . . . .		6
	2.1	SPI interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	2.2	SPI diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
		2.2.1 Fault detection interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
3	API specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		8
	3.1	Function definition for motor power board configuration . . . . . . . . . . . . . .	9

3.1.1 SetCom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.2 Function definitions for the motor power board diagnosis . . . . . . . . . . . . 10

3.2.1 ShortMotorDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2.2 LowVoltPreDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2.3 SPINGFailDetect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3 Type definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.1 DIAG1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.2 DIAG2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.3 DIAG3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		13
4	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	17

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AN2500	List of tables

List of tables

Table 1. SPI master signal description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 2. SPI commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 3. DIAG1 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Table 4. DIAG2 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Table 5. DIAG3 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Table 6. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

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List of figures	AN2500

List of figures

Figure 1. ST10 EMC library structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. SPI registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 3. Fault signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

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AN2500	Functions set overview

1 Functions set overview

The SPI_FS is a set of functions included in ST10 electric motor control library (see Figure 1). It uses the ST10 peripheral SSC configured like SPI interface to allow the full

duplex communication with MP49 (slave) and to set a specific MP49 parameters configuration or diagnosis requests, see Table 2.

Figure 1.

ST10 EMC library structure

ST10 EMCL

Flux

Sinusoidal

Observer

SPI

Encoder

Hall sensors

Current sensing

PWM

Oriented

Control

Leunberger

Driver

Driver

Driver

Driver

Driver

Control

spi.c

spi.h

The communication between the CPU board and the motor power board is based on SPI interface with a chip select (4 signals in total).

The exchanged data set some parameters and the command to read the status of the motor power board. The configuration command allows to choose the shape of fault pin output signal. Another subset of commands allows to send diagnosis requests to read the status of the inverter driver and of the powerMOS.

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MP49 to CPU board communication overview	AN2500

2 MP49 to CPU board communication overview

The MP49 motor power board communicates with the CPU board using an SPI interface and using a fault signal to report to the CPU faults as soon as they are detected.

The MP49 requires only to be configured after reset and the CPU does not need any action after initialization as long as the fault pin is not active.

2.1SPI interface

The SPI interface provides a full-duplex, synchronous serial communication between microcontrollers and peripherals. It is based upon a Master-Slave protocol where the master is the device that drives the serial clock signal (SCLK), used to synchronize the communication.

The SPI bus consists of four wires, Serial Clock signal (SCLK), Master Transmit / Slave

Receive (MTSR), Master Receive / Slave Transmit (MRST), and Chip Select (CS), which carry information between the devices connected to the bus (see Figure 2).

Table 1.	SPI master signal description
	Name	Direction	Description
	MTSR	Output	SPI Serial Data Output. Serial data output from
			the SPI Master to a SPI slave.
	MRST	Input	SPI Serial Data Input. Serial data input from a
			SPI slave to the SPI Master.
	SCLK	Output	SPI Serial Clock. Normally high, and the correct
			clock pulse number is sixteen.
			SPI Slave Selects. Normally high, this input
	CS	Output	signal starts the communication when it is forced
			low (for selecting the MP49 board use pin P2.7).

Figure 2. SPI registers

The SCLK control line is driven by the SPI Master and regulates the flow of data bits, so that data is shifted on falling edge of SCLK and is sampled on the opposite edge when the data is stable.

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