Hi, back again.
It seems to me that you actually measure RS232 signals at RS232 level (on the Cannon connector). For
proper debugging you need to measure actual RxD and TxD signals *between* 232 level shifter and MCU (3V logic). I still think that the main trouble can be seen there - I mean 232 level shifter not working properly right after power up. What you observe there (RS232 levels) won't be reflected correctly at the 3V side.
An "oscillograph" of the 3V signals would be very helpful.
You should see the signals similar to what is shown on the attached picture (all levels are at 3V, at the MCU).
If you have RESET pin available (e.g. through button), you may try different way of starting bootloader:
- power up the device
- press RESET button (and do not release it)
- start hc08sprg.exe
- release RESET button
This way the level shifters should be functional once the MCU starts executing bootloader code.
Regards, Pavel ok2ucx, Freescale CZ
P.S. You've indicated that the transmit line (from MCU to PC) stays at 0V. This is illegal RS232 level, which should be below -3V for log. "1" and above 3V for log. "0", if I remember well. Anything else may not be interpreted correctly.
Please, double check your RS232 level shifter if it's working properly.
P.S.2: I also don't understand this "The Receive line (from PC to uP) is at -8 Volts and will cause a 1ms pulse that causes the uP to reset." - no RS232 signal cannot and will not reset the MCU (directly). -8V level (from PC) will be translated to log. "1" (3V) level
bootack.png
Message Edited by t.dowe on 2009-09-03 05:42 PM