MC68hc908AZ60 can be programmed
in circuit (without removing from the board) 1. Make
connections as it's shown on the picture
below. Maybe some connections are already done, so check the circuit.
It's the best to cut the tracks which 68hc908 use for entering monitor
mode (Especially IRQ, PAO and RESET). The voltage measured on IRQ have to be
8-9V. 2. Select correct baud rate. This can be automatically
by pushing Auto Baud Rate button. If auto method is not successful
(this is maybe the first indicating that something is wrong),
the baud rate must be set manual in accordance with the
table below
|
Baud rate
|
|
Quartz Resonator
|
PCT3=0
|
PCT3=1
|
|
1MHz
|
1800
|
900
|
|
2MHz
|
3600
|
1800
|
|
4MHz
|
7200
|
3600
|
|
4.194MHz
|
7680
|
3840
|
|
4.9152MHz
|
8861
|
4430
|
|
8MHz
|
14400
|
7200
|
|
16MHz
|
28800
|
14400
|
For example: If PTC3 = 0, quartz =
8MHz, baud rate = 14400 if PTC3 = 1 (VDD), quartz = 8MHz, baud rate =
7200 A special baud rate must be set in mcu with mask: 8H62A
mask with quartz 8Mhz, PTC3 = 5V - baud rate 7812 2J74Y mask with
quartz 8 Mhz, PTC3 = 5V - baud rate 7246 1H56A at 7200 baud 0J66D
at 7200 baud
3. Push Read button (with secure bytes - checked) . If
reading is unsuccessful, you have to do power up reset (switch off power
supply and wait until Vdd<0.1V and Reset<0.1V) then switch on power
supply, push Read button without checked Security Bytes check box. Always when
you have errors, you must to do power up reset
|