ST72F324J6TATX View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72F324J6TATX

8-bit MCU for automotive, 3.8 to 5.5V operating range with 8 to 32 Kbyte Flash, 10-bit ADC, 4 timers, SPI, SCI

STMicroelectronics 

Known limitations

ST72324xx-Auto

15.7 SCI wrong break duration

Description

A single break character is sent by setting and resetting the SBK bit in the SCICR2 register.

In some cases, the break character may have a longer duration than expected:

● 20 bits instead of 10 bits if M = 0

● 22 bits instead of 11 bits if M = 1

In the same way, as long as the SBK bit is set, break characters are sent to the TDO pin.

This may lead to generate one break more than expected.

Occurrence

The occurrence of the problem is random and proportional to the baud rate. With a transmit

t(s) frequency of 19200 baud (fCPU = 8MHz and SCIBRR = 0xC9), the wrong break duration

occurrence is around 1%.

c Workaround

du If this wrong duration is not compliant with the communication protocol in the application,

ro software can request that an Idle line be generated before the break character. In this case,

P the break duration is always correct assuming the application is not doing anything between

te the idle and the break. This can be ensured by temporarily disabling interrupts.

le The exact sequence is:

o 1. Disable interrupts

bs 2. Reset and set TE (IDLE request)

O 3. Set and reset SBK (break request)

) - 4. Re-enable interrupts

Obsolete Product(s 15.8

Negative current injection on pin PB0

Negative current injection on pin PB0 degrades the performance of the device and is not

allowed on this pin.

190/193

Doc ID 13841 Rev 1

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