ST72325 STMICROELECTRONICS [STMicroelectronics], ST72325 Datasheet - Page 191

• Manufacturer Part Number: ST72325
• Description: 8-BIT MCU WITH 16 TO 60K FLASH/ROM, ADC, CSS, FIVE TIMERS, SPI, SCI, I2C INTERFACE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST72325
KNOWN LIMITATIONS (Cont’d)
15.1.3 SCI Wrong Break duration
Description
A single break character is sent by setting and re-
setting the SBK bit in the SCICR2 register. In
some cases, the break character may have a long-
er 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 expect-
ed.
Occurrence
The occurrence of the problem is random and pro-
portional to the baudrate. With a transmit frequen-
cy of 19200 baud (f
BRR=0xC9), the wrong break duration occurrence
is around 1%.
Workaround
If this wrong duration is not compliant with the
communication protocol in the application, soft-
ware can request that an Idle line be generated
before the break character. In this case, the break
duration is always correct assuming the applica-
tion is not doing anything between the idle and the
break. This can be ensured by temporarily disa-
bling interrupts.
The exact sequence is:
- Disable interrupts
- Reset and Set TE (IDLE request)
- Set and Reset SBK (Break Request)
191/193
CPU
=8MHz and SCI-
- Re-enable interrupts
15.1.4 16-bit Timer PWM Mode
In PWM mode, the first PWM pulse is missed after
writing the value FFFCh in the OC1R register
(OC1HR, OC1LR). It leads to either full or no PWM
during a period, depending on the OLVL1 and
OLVL2 settings.
15.1.5 I2C Multimaster
In multimaster configurations, if the ST7 I2C re-
ceives a START condition from another I2C mas-
ter after the START bit is set in the I2CCR register
and before the START condition is generated by
the ST7 I2C, it may ignore the START condition
from the other I2C master. In this case, the ST7
master will receive a NACK from the other device.
On reception of the NACK, ST7 can send a re-start
and Slave address to re-initiate communication
15.1.6 ADC Accuracy in 16/32K Flash Devices
The ADC accuracy in 16/32K Flash Devices devi-
ates from table in
follows:
Symbol
|E
|E
|E
|E
|E
O
G
D
T
L
|
|
|
|
|
section 12.12.3 on page 172
Max
4.5
6
5
2
3
2)
Unit
LSB
as