MC68HC908JB8 Datasheet, PDF (170/286 Pages) Motorola, Inc – MICROCONTROLLERS

Monitor ROM (MON)
10.4.3 Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 10-3 and Figure 10-4.)
NEXT
START
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 ^STOP BIT
BIT
Figure 10-3. Monitor Data Format
NEXT
START
START
$A5 BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 STOP BIT
BIT
BREAK
START
BIT BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
STOP
BIT 7 BIT ^NEXT
START
BIT
Figure 10-4. Sample Monitor Waveforms
The data transmit and receive rate can be anywhere from 4800 baud to
28.8k-baud. Transmit and receive baud rates must be identical.
10.4.4 Echoing
As shown in Figure 10-5, the monitor ROM immediately echoes each
received byte back to the PTA0 pin for error checking.
SENT TO
MONITOR
ECHO
READ
READ ADDR. HIGH ADDR. HIGH ADDR. LOW ADDR. LOW DATA
Figure 10-5. Read Transaction
RESULT
Any result of a command appears after the echo of the last byte of the
command.
Technical Data
170
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Monitor ROM (MON)
Freescale Semiconductor