MC68HC908JL3E Datasheet, PDF (114/226 Pages) Motorola, Inc – Microcontrollers

Monitor ROM (MON)
9.4.3 Data Format
Communication with the monitor ROM is in standard non-return-to-zero
(NRZ) mark/space data format. (See Figure 9-3 and Figure 9-4.)
NEXT
START
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 ^STOP BIT
BIT
Figure 9-3. Monitor Data Format
$A5
BREAK
START
BIT BIT 0
START
BIT BIT 0
BIT 1
BIT 1
BIT 2
BIT 2
BIT 3
BIT 3
BIT 4
BIT 4
BIT 5
BIT 5
BIT 6
BIT 6
BIT 7
BIT 7
STOP
BIT
STOP
BIT
NEXT
START
BIT
NEXT
START
BIT
Figure 9-4. 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.
9.4.4 Echoing
As shown in Figure 9-5, the monitor ROM immediately echoes each
received byte back to the PTB0 pin for error checking.
SENT TO
MONITOR
ECHO
READ
READ ADDR. HIGH ADDR. HIGH ADDR. LOW ADDR. LOW DATA
Figure 9-5. Read Transaction
RESULT
Any result of a command appears after the echo of the last byte of the
command.
Technical Data
114
MC68H(R)C908JL3E/JK3E/JK1E — Rev. 2.0
Monitor ROM (MON)
MOTOROLA