AN2502 Freescale Semiconductor / Motorola, AN2502 Datasheet - Page 36

• Manufacturer Part Number: AN2502
• Description: Using Two Channels of the HC08 TIM to Achieve a Full-Duplex Software SCI
• Manufacturer: Freescale Semiconductor / Motorola

AN2502/D
36
TEMPORAL PARITY
CONFIGURE CH1
AS SET ON OC
TOGGLE
1
YES
Using Two Channels of the HC08 TIM to Achieve a Full-Duplex Software SCI
SET TIME FOR NEXT
PROGRESS FLAG
AS CLEAR ON OC
SCTSRH:SCTSRL
CONFIGURE CH1
OC (1 BIT-TIME)
CLEAR CARRY
PROGRESS?
CARRY SET?
NO
TX_ISR
Tx IN
Tx IN
ROR
SET
RTI
NO
Figure 35. Transmit ISR — Enhanced Mode
Freescale Semiconductor, Inc.
YES
For More Information On This Product,
3
ADD 1 BIT-TIME TO
DISABLE CH1
Tx CHANNEL
YOUR CODE
ACC <- CCR
SET CARRY
PTYTX <- 0
STBTX <- 0
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PTYTX
HERE
= 1?
2
4
YES
NO
YES
YES
YES
TO SEND START BIT
ADD 1 BIT-TIME TO
DEPENDING ON
MSB TO INDICATE
PROGRESS FLAG
AS CLEAR ON OC
SET LEFT BIT OF
CONFIGURE CH1
Tx SHIFT REG =
TRANSMITTER
Tx DATA REG
EMPTY FLAG
Tx CHANNEL
END OF Tx
ER EMPTY
FLAG SET
TIEN = 1
CLEAR
STBTX
SB = 1
Tx IN
= 1?
SET
Tx
YES
NO
M
NO
4
PERIOD (1 BIT-TIME)
2
TRANSMISSION
CLEAR CARRY
SCTSRH:SCTSRL
SET NEXT OC
ACC <- CCR
CCR <- ACC
SHIFT REG
= #0x0000?
ROR
1
NO
INTO CARRY FLAG
COPY PARITY BIT
ACC <- CCR
PARITY LEVEL
YES
CALCULATE
PEN = 1?
PTYTX <- 1
STBTX <- 0
2
YES
MOTOROLA
NO
3