ST72521AR9TB Ver la hoja de datos (PDF) - STMicroelectronics

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ST72521AR9TB

8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE

STMicroelectronics 

ST72521

To enable programming of all flash sectors, the

device must leave USER mode and be configured

in ICC mode. Once in ICC mode, the ICC protocol

enables an ST7 microcontroller to communicate

with an external controller (such as a PC). ICC

mode is entered by applying 39 pulses on the IC-

CDATA signal during reset. To enter ICC mode,

the device goes through other modes, some

modes are critical because the I/Os PG[7:0] and

PH[7:0] are forced to output push-pull.

Impact on the Application

The PG and PH I/O ports are forced to output

push-pull during three pulses on ICCDATA. In cer-

tain circumstances, this behaviour can lead to a

short-circuit between the I/O signals and VDD, VSS

or an output signal of another application compo-

nent.

In addition, switching these I/Os to output mode

can cause the application to leave reset state, dis-

turbing the ICC communication and preventing the

user from programming the flash.

15.2.9 CAN Cell Limitations

Limitation1

ST72F521

Rev “R” & “Q”

(Flash)

Omitted SOF bit

x

CPU write access

(more than one cycle)

x

corrupts CAN frame

Unexpected Mes-

sage transmission

x2

Bus Off State Not En-

tered

WKPS Functionality

x4

ST72F521 “S”

(Flash) &

ST72521 “W”

(ROM)

x

x

x3

x

x=limitation present

1For details see Section 10.8.5 on page 144

2Software workaround possible using modified

WKPS bit.

3No software workaround possible. WKPS bit not

modified.

4Functionality modified for Unexpected Message

Transmission workaround.

207/211

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