AN2502 Freescale Semiconductor / Motorola, AN2502 Datasheet - Page 37

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

MOTOROLA
Using Two Channels of the HC08 TIM to Achieve a Full-Duplex Software SCI
NO
SET NEXT OC PERIOD
(1.3 BIT-TIMES x 31 OF
PIN CHECK LATENCY)
SCRSRH TO ADJUST
MSB TO INDICATE
DEPENDING ON M
PROGRESS FLAG
SET LEFT BIT OF
RECEIVED DATA
IN PROGRESS?
SET MSB IN
END OF RX
ENABLED?
SET Rx IN
RX_ISR
Rx
Rx
Freescale Semiconductor, Inc.
Figure 36. Receive ISR — Enhanced Mode
YES
NO
For More Information On This Product,
YES
1
Go to: www.freescale.com
PERIOD (1 BIT-TIME)
CONFIG CH0 AS OC
WITH PIN UNDER
COPY RPIN INTO
PORT CONTROL
PARITY ERROR
SET NEXT OC
CARRY FLAG
CALCULATE
YOUR CODE
PARITY BIT
PTYRX <- 0
STBRX <- 1
PUSH CCR
ENABLED?
PTYRX = 1
STBRX = 1
POP ACC
HERE
AND
RTI
YES
YES
NO
NO
YES
NO
ON FALLING EDGES
CONFIG CH0 AS IC
TEMPORAL PARITY
FRAMING ERROR
RIEN = 1?
CARRY SET?
CALCULATE
STOP BITS
PTYRX <- 1
STBRX <- 1
POP CCR
PTYRX = 0
STBRX = 1
POP ACC
(SB = 1) ?
TOGGLE
NO
TWO
AND
YES
YES
YES
NO
NO
NO
NO
SCRSRH:SCRSRL
PROGRESS FLAG
FRAMING ERROR
Rx DATA REG =
ADJUST DATA
Rx SHIFT REG
CARRY SET?
CLEAR Rx IN
Rx IS FULL?
CALCULATE
PTYRX <- 1
STBRX <- 0
FULL FLAG
FRAMING
PTYRX = 1
STBRX = 1
POP ACC
ORE <- 0
ORE <- 1
ERROR?
SET Rx
FE <- 0
ROR
AND
YES
YES
YES
YES
NO
NO
1
AN2502/D
Software
37