
Serial communications interface (SCI) ST72321xx-Auto
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Figure 64. SCI baud rate and extended prescaler block diagram
Framing error
A framing error is detected when:
● The stop bit is not recognized on reception at the expected time, following either a de-
synchronization or excessive noise.
● A break is received.
When the framing error is detected:
● The FE bit is set by hardware.
● Data is transferred from the Shift register to the SCIDR register.
● No interrupt is generated. However this bit rises at the same time as the RDRF bit
which itself generates an interrupt.
The FE bit is reset by a SCISR register read operation followed by a SCIDR register read
operation.
TRANSMITTER
RECEIVER
SCIETPR
SCIERPR
EXTENDED PRESCALER RECEIVER RATE CONTROL
EXTENDED PRESCALER TRANSMITTER RATE CONTROL
EXTENDED PRESCALER
CLOCK
CLOCK
RECEIVER RATE
TRANSMITTER RATE
SCIBRR
SCP1
f
CPU
CONTROL
CONTROL
SCP0 SCT2 SCT1 SCT0 SCR2 SCR1 SCR0
/PR
/16
CONVENTIONAL BAUD RATE GENERATOR
EXTENDED RECEIVER PRESCALER REGISTER
EXTENDED TRANSMITTER PRESCALER REGISTER
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