AN2502 Freescale Semiconductor / Motorola, AN2502 Datasheet - Page 15

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

Transmission in
Enhanced Mode
MOTOROLA
Using Two Channels of the HC08 TIM to Achieve a Full-Duplex Software SCI
The user must be aware that any code executed in this subroutine will affect
the MCU performance because the code will be executed in the interrupt
service routine.
Steps 1 and 2 are the same in normal mode and enhanced mode:
Steps 3 through 5 are specific to enhanced mode:
If the parity bit is enabled
transmission. The following formula shows the computation of the parity bit to
be sent:
1. Transmission of the start bit
2. Data bits transmission process
3. Number of data bits to be transmitted
4. Parity bit computation
5. Second stop bit is sent when enabled in the
Freescale Semiconductor, Inc.
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TPTY = Data bit (0) ⊕ Data bit (1) ⊕ … ⊕ Data bit (N-1)
Parity bit to be transmitted = (TPTY ⊕ PTY)
Table 5. Reception Completed Subroutine Enable Bit
Figure 25. Data Bit Transmission in Enhanced Mode
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START BIT
1 BIT-TIME
RIEN
1
0
(PEN
OUTPUT COMPARE LEVEL
DEPENDING ON DATA BIT
TRANSMITTED
DATA BIT
= 1), the parity bit is sent after the last data bit
FIRST
Subroutine disabled
Subroutine enabled
Configuration
DATA BIT
SECOND
rSCCR
AN2502/D
Modes
15