Freescale Semiconductor MC68HC908MR32 Manual Do Utilizador

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MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
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Freescale Semiconductor
18.3.1.5  Echoing
As shown in 
, the monitor ROM immediately echoes each received byte back to the PTA0 
pin for error checking. 
Figure 18-11. Read Transaction
Any result of a command appears after the echo of the last byte of the command.
18.3.1.6  Break Signal
A start bit followed by nine low bits is a break signal. See 
. When the monitor receives a break 
signal, it drives the PTA0 pin high for the duration of two bits before echoing the break signal.
Figure 18-12. Break Transaction
18.3.1.7  Commands
The monitor ROM uses these commands (see 
):
READ, read memory
WRITE, write memory
IREAD, indexed read
IWRITE, indexed write
READSP, read stack pointer
RUN, run user program
ADDR. HIGH
READ
READ
ADDR. HIGH
ADDR. LOW
ADDR. LOW
DATA
ECHO
SENT TO
MONITOR
RESULT
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
MISSING STOP BIT
2--STOP-BIT DELAY BEFORE ZERO ECHO