ST72361 Datasheet, PDF (124/224 Pages) STMicroelectronics – 8-BIT MCU WITH FLASH OR ROM, 10-BIT ADC, 5 TIMERS, SPI, 2x LINSCI

ST72361
LINSCI™ SERIAL COMMUNICATION INTERFACE (SCI Mode) (Cont’d)
10.7.5 SCI Mode - Functional Description
10.7.5.1 Serial Data Format
Conventional Baud Rate Generator Mode
The block diagram of the Serial Control Interface
in conventional baud rate generator mode is
shown in Figure 1.
Word length may be selected as being either 8 or 9
bits by programming the M bit in the SCICR1 reg-
ister (see Figure 2).
The TDO pin is in low state during the start bit.
It uses four registers:
The TDO pin is in high state during the stop bit.
– 2 control registers (SCICR1 and SCICR2)
– A status register (SCISR)
– A baud rate register (SCIBRR)
Extended Prescaler Mode
Two additional prescalers are available in extend-
ed prescaler mode. They are shown in Figure 3.
An Idle character is interpreted as a continuous
logic high level for 10 (or 11) full bit times.
A Break character is a character with a sufficient
number of low level bits to break the normal data
format followed by an extra “1” bit to acknowledge
the start bit.
– An extended prescaler receiver register (SCIER-
PR)
– An extended prescaler transmitter register (SCI-
ETPR)
Figure 78. Word Length Programming
9-bit Word length (M bit is set)
Data Character
Possible
Parity
Bit
Next Data Character
Next
Start
Bit ^Bit0
Bit1
Bit2
Bit3
Bit4 Bit5
Bit6
Bit7 Bit8
Stop
Bit
Start
Bit
Start
Idle Line
Bit
Break Character
Extra ^Start
’1’ ^Bit
8-bit Word length (M bit is reset)
Data Character
Start
Bit ^{Bit0 Bit1 Bit2 Bit3 Bit4 Bit5}
Possible
Parity
Bit
Bit6
Bit7
Stop
Bit
Next Data Character
Next
Start
Bit
Idle Line
Start
Bit
Break Character
Extra
’1’
Start
Bit
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