ST AN2695 Application note

AN2695

Application note

Differences between the ST10F276Z5 and its emulator

Introduction

The ST10F276Z5 is a new device of the ST10 family. Compared to the ST10F269Zx, it has more Flash memory, more RAM and better CPU performance. The serial communication peripherals have been enhanced by the addition of one I2C, one ASC (asynchronous serial interface) and one SSC (synchronous serial interface) to the existing ones. CAN communication has been also improved by the replacement of B-CAN modules by C-CAN modules. These new features widely extend the application field of the ST10 family.

This application note covers the design and the emulation aspects in using the

ST10F276Z5.

March 2008

Rev 1

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www.st.com

Contents	AN2695

Contents

1	ST10F276Z5 Xperipheral support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		3
	1.1	Real-time aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	1.2	Fully supported peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
2	Peripherals partly supported by the emulators . . . . . . . . . . . . . . . . . . .		4
	2.1	A/D converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4

2.1.1 ADC calibration process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.2 ADC conversion timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.3 ADC power consumption control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Real-time clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Standby RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3	ST10F276Z5 registers not supported by the emulator . . . . . . . . . . . . .		6
	3.1	Software advice for non-implemented registers . . . . . . . . . . . . . . . . . . . . .	6
	3.2	Port4 registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	3.3	Port5 registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	3.4	XPERCON register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7

4	ST10F276Z5 registers partly supported by the emulator . . . . . . . . . .		. 8
	4.1	WDTCON register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
5	ST10F276Z5 peripherals not supported by the emulators . . . . . . . . . .		9
	5.1	ST10F276Z5 Flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
	5.2	Bootstrap and Alternate Boot mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
6	Maximum frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		10
7	DC/AC parameter differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		11
8	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		12

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AN2695	ST10F276Z5 Xperipheral support

1 ST10F276Z5 Xperipheral support

CAN module, I2C, second ASC unit, second SSC unit, second PWM (pulse-width modulation) unit, real-time clock, interrupt subnode controller and clock-out programmable generator are ST10F276Z5 Xperipherals.

1.1Real-time aspects

All Xperipherals are functionally supported but not at full speed.

The ST10F276Z5 silicon runs with 2 wait-states while the emulator requires 4 wait-states with those peripherals. This limitation is independent of the frequency of the CPU clock and is applicable to any Xperipheral except for memories.

1.2Fully supported peripherals

Compared to the ST10F269Zx, the ST10F276Z5 has the following new peripherals: CAN module, I2C, a second ASC unit, a second SSC unit, a second PWM unit, interrupt subnode controller and clock-out programmable generator.

All these new peripherals are fully functionally supported in emulation if the initialization sequence of the XPEREMU register is implemented. Refer to the latest ST10F276Z5 datasheet available from the STMicroelectronics website www.st.com.

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Peripherals partly supported by the emulators	AN2695

2 Peripherals partly supported by the emulators

Some of the ST10F276Z5 peripherals are partly supported by the emulators. This section describes the limitations encountered in emulating these peripherals.

2.1A/D converter

Compared to that of the ST10F269Zx, the ST10F276Z5 ADC has been improved to support 24 channels instead of 16 and to have a faster conversion time. These improvements have a small impact on the emulation and compatibility with the ST10F269Zx. They are explained in the following sections.

2.1.1ADC calibration process

Description: the ST10F276Z5 ADC auto-calibration process cannot be interrupted for conversion. It was interruptible with the ST10F269Zx and the ST10 bond-out. The duration of the calibration of the ST10F276Z5 is 40 650 cycles, which is very close to the 40 000 CPU clock cycles of the ST10F269Zx. The calibration starts automatically on each Reset (external_hardware, internal_hardware or software reset). During the auto-calibration, the ADCON.ADBSY bit is set (same behavior as the ST10F269Zx and ST10 bond-out).

Software impact: before starting the 1st ADC conversion, the application software should check the busy bit in the ADCON register (ADBSY=1 during auto-calibration). There is no impact for subsequent ADC configuration changes.

Hardware impact: no impact.

ST10F276Z5 emulation impact: no impact if ST’s advice is implemented. Real-time differences due to the change in calibration process duration have to be analyzed for each application.

Hint: check the busy bit in ADCON before the 1st initialization of the ADC.

2.1.2ADC conversion timings

Description: to allow faster conversion, the ADC sampling clock has been changed. For the same software configuration, this results in different sampling times for the ST10F276Z5 compared to the ST10F269Zx and the ST10-emulator. To keep the same real-time behavior, the ADC overall timings between 2 consecutive conversions have not been changed.

Software impact: to avoid issues caused by sampling time not coherent with external RC filters, it is proposed to modify the software to check which processor of the ST10F276Z5 or the emulator is running the software (by checking ID-chip register), and to set the ADCON sampling clock accordingly.

Hardware impact: no impact.

ST10F276Z5 emulation impact: no impact if ST’s advice is implemented.

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