MC908AB32CFUE Datasheet, PDF (162/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Monitor ROM (MON)
10.4.3 Echoing
As shown in Figure 10-4, the monitor ROM immediately echoes each
received byte back to the PTA0 pin for error checking.
Any result of a command appears after the echo of the last byte of the
command.
SENT TO
MONITOR
READ
READ ADDR. HIGH ADDR. HIGH ADDR. LOW ADDR. LOW DATA
ECHO
RESULT
Figure 10-4. Read Transaction
10.4.4 Break Signal
A start bit followed by nine low bits is a break signal. (See Figure 10-5.)
When the monitor receives a break signal, it drives the PTA0 pin high for
the duration of two bits before echoing the break signal.
MISSING STOP BIT
TWO-STOP-BIT DELAY BEFORE ZERO ECHO
01234567
01234567
Figure 10-5. Break Transaction
Technical Data
162
Monitor ROM (MON)
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor