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 I
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.
2
C, one ASC (asynchronous serial
March 2008 Rev 1 1/13
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.
1.1 Real-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.
1.2 Fully supported peripherals
Compared to the ST10F269Zx, the ST10F276Z5 has the following new peripherals: CAN
module, I
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.
2
C, a second ASC unit, a second SSC unit, a second PWM unit, interrupt subnode
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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.
2.1 A/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.
2.1.1 ADC 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 1
check the busy bit in the ADCON register (ADBSY=1 during auto-calibration). There is no
impact for subsequent ADC configuration changes.
st
ADC conversion, the application software should
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 1
2.1.2 ADC 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.
st
initialization of the ADC.
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AN2695 Peripherals partly supported by the emulators
2.1.3 ADC power consumption control
Description: the ST10F276Z5 ADC can be shut off to further optimize power consumption.
This is done through the ADCON.6 (ADOFF) bit. This bit is not supported by the ST10 bondout. Application software should only write to this bit and not check it.
Software impact: no impact if ST’s advice is implemented.
Hardware impact: no impact.
ST10F276Z5 emulation impact: no impact if ST’s advice is implemented.
2.2 Real-time clock
Description: an external oscillator is required for the RTC clock of the ST10F276Z5
emulators because the low-power oscillator used to clock the ST10F276Z5 RTC is not
supported by the emulators.
Also, as the ST10F276Z5 in emulation mode cannot know if the bond-out is executing a
power-down instruction, the RTCCON.7 (RTOFF) bit cannot be emulated, only the default
value’0’ (RTC keeps running during power-down) can be supported.
Partial implementations: some emulators do not gate the RTC clock to block it when the
emulation is stopped. Some emulators also do not decode the RTCCON.8 (OSC) and
RTCCON.9 (OFF32) bits. Please, contact your emulator provider to have more information
on the RTC support.
Software impact: no impact for the Idle mode. For power-down, please refer to the
documentation given by the emulator supplier.
Hardware impact: external crystals for RTC are not supported. An external oscillator is
required to supply the emulator RTC input clock.
ST10F276Z5 emulation impact: no impact in Idle mode if ST’s advice is implemented. For
power-down, please refer to the documentation given by the emulator supplier.
2.3 Standby RAM
Description: the contents of the ST10F276Z5 standby RAM are not lost when the main
supply is switched off. If the standby supply is switched off while the circuit has no main
supply, the standby RAM contents are lost. ST10F276Z5 emulators do not support the
standby pin and their supply is different from the application supply (ST10 bond-out is still
supplied if main application is switched off).
Software impact: no impact.
Hardware impact: standby functionality pin is not fully supported.
ST10F276Z5 emulation impact: the main functionality of the standby RAM is emulated.
The ST10 bond-out memory contents are kept when the main supply is switched off but the
standby RAM functionality is not fully supported. The RAM contents are not lost when the
main and standby supplies of the application are switched off.
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ST10F276Z5 registers not supported by the emulator AN2695
3 ST10F276Z5 registers not supported by the emulator
This section describes all the emulation issues caused by the non-implementation of some
ST10F276Z5 registers in the ST10 bond-out and ST10F276Z5 emulators.
3.1 Software advice for non-implemented registers
When an ST10F276Z5 register is not implemented in the bond-out:
● avoid unnecessary data read and check operations in this register
● if some read accesses in user mode are necessary, use the CPU IDCHIP register to
detect which CPU is running the code. Then, allow the check on this register only for
the ST10F276Z5. If running from the bond-out, use a predefined, but non-initialized,
memory variable to set the desired configuration during emulation.
3.2 Port4 registers
Description: the ST10F276Z5 ODP4 register is not implemented on the ST10 bond-out.
This register is used to set the CAN-TxD pin handling alternate functions in push-pull or
open-drain. Usually, the open drain configuration on the CAN-TxD lines is used to put two
CAN modules in parallel.
Software impact: application software should only write to this register.
Hardware impact: no hardware impact if ST’s advice is implemented by the emulator party
(check with your emulator supplier).
ST10F276Z5 emulation impact: no impact if ST’s advice is implemented and if the
contents of the register are fixed at initialization (never changed during run time) and if the
emulator is properly configured.
Hint: use the CANPAR bit in the XMISC register to configure the two modules in parallel.
Note: This limitation is already present in the ST10F269Zx.
3.3 Port5 registers
Description: the ST10F276Z5 P5DIDIS register is not implemented in the emulator. This
register is used to enhance the accuracy of analog inputs within the temperature and supply
voltage ranges.
Software impact: application software should only write to this register.
ST10F276Z5 emulation impact: no impact if software recommendations are used.
Note: This limitation is already present in the ST10F269Zx.
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AN2695 ST10F276Z5 registers not supported by the emulator
3.4 XPERCON register
Description: this register is not implemented in the emulator, but is implemented in the
ST10F276Z5. The emulator XPeripherals are enabled by the user in the emulator
environment.
Software impact: application software should only write to this register.
ST10F276Z5 emulation impact: no impact if the software recommendations are used and
if the emulator is properly configured.
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ST10F276Z5 registers partly supported by the emulator AN2695
4 ST10F276Z5 registers partly supported by the
emulator
This section describes all the emulation issues caused by ST10F276Z5 registers that are
implemented in the emulator in a different way in the ST10F276Z5 (new bits added or
modified bit functionality).
4.1 WDTCON register
Description: this register is implemented in the ST10 bond-out chip but not all the bits used
to identify the reset cause are implemented.
Software impact: the cause of the reset cannot by known by software when using
emulators.
ST10F276Z5 emulation impact: it is proposed:
● to simulate the reset causes during emulation,
● to write the reset procedure so as to detect, via the IDCHIP register, which of the
ST10F276Z5 or the bond-out is running the software. Then, to use a non-initialized
variable (initialized by the user before running emulation) to check the reset cause
when running code with the bond-out.
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AN2695 ST10F276Z5 peripherals not supported by the emulators
5 ST10F276Z5 peripherals not supported by the
emulators
This section describes all emulation issues caused by peripherals not supported by the
ST10 emulators.
5.1 ST10F276Z5 Flash memory
Description: in emulation, the bond-out is running code from the RAM mapped into the
ST10 bond-out memory space.
ST10F276Z5 emulation impacts:
● the automatic remapping of the Flash memory in normal or bootstrap mode is not
supported. This leads to have a specific software for each memory mapping.
● the Flash memory specificities are not supported (Flash programming commands are
not recognized, reading any Flash memory register leads to undefined contents).
ST10F276Z5 Flash memory limitations: during emulation, some emulators do not protect
the emulated Flash memory against write access by the ST10F276Z5. The bond-out, when
properly configured, protects the internal Flash memory. Then, external hardware placed on
the emulated XFlash can protect it during emulation.
Please, contact your emulator provider to have more information on the Flash memory
support.
5.2 Bootstrap and Alternate Boot mode
Description: the ST10F276Z5 bootstrap modes cannot be supported by the emulator. The
ST10F276Z5 has a dual bootstrap via UART or CAN and supports alternate boot.
This limitation is not specific to the ST10F276Z5, it is also applicable to the ST10F269Zx.
ST10F276Z5 emulation impacts:
● the dual boot is not supported
● alternate bootstrap is not supported (ST10 bond-out does not decode Port0
configuration for alternate boot).
To debug the bootstrap software routines, it is required to have a specific software for this
mode. This specific software, loaded into the emulator memory, must have the same boot
software as the one inside the boot-Flash of the ST10F276Z5, and all the needed software
from the other blocks of the Flash memory.
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Maximum frequency AN2695
6 Maximum frequency
Processed in 0.18 µm technology, the ST10F276Z5 is designed to run at up to 64 MHz.
The emulators’ maximum frequency is limited to 50 MHz. Real-time emulation is limited to
50 MHz.
Application debugging at higher frequencies is possible by using embedded monitors.
Important note: it is highly recommended not to overclock emulators.
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AN2695 DC/AC parameter differences
7 DC/AC parameter differences
Although minimized as much as possible, there are differences in DC and AC parameters.
For detailed differences in DC or AC parameters, please refer to the latest ST10F276Z5
datasheet.
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Revision history AN2695
8 Revision history
Table 1. Document revision history
Date Revision Changes
06-Mar-2008 1 Initial release.
12/13
AN2695
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