Terrasmark Terrasmark

5x7 LED Dot-matrix Disp. Sys. (MC68HC908GP32, MAX6952, WinIDE)

Discussion created by Terrasmark Terrasmark on Oct 12, 2008
Latest reply on Oct 12, 2008 by donw

Hello. I'm doing a project which is to program 8 digits of 5x7 bicolour dot-matix displays using the MC68HC908GP32 (40-pin PDIP) via 4 MAX6952 (40-pin PDIP) display drivers. I'm using only these ICs due to material constaints.

 

My progress so far:-
1) Built programming board (normal monitor mode circuit).
2) Entered monitor mode (PROG08SZ ver. 2.22.00.00).

 

The HC908's ports B (PTB0-7) are connected to 8 (normal) LEDs with 330ohm resistors in between each one. This's to (prog.) test the HC908. Vdd = 5V. Measured Vtst = 8.3V.

 

My current prob. is I can't blank check, erase, prog. module whatsoever. Double-clicking the commands causes PROG08SZ to stall indefinitely without any further confirmation, but clicking other buttons is still OK, including the ESC key to abort command. Selecting "EM Erase module" produces the stat. "Erasing.", then slash characters (- \ | / - ...) appear to rotate forever. Only the ESC key stops the process.

 

I've tried
1) different sets of MC68HC908GP32.
2) a simpler normal monitor mode with the 74HC125 replaced with a diode.
3) changing the 9.1V Zener diode to a 7.5V one.
4) using both AC/DC power supply & cell batteries (4xAA 1.5V batteries, non-rechargeable with voltage divider to produce 5V) for Vdd., but maintained @ 5V.
5) setting different baud rates for the class & com. serial port settings.
6) setting com. serial port flow ctrl. to "None", "Xon / Xoff" & "Hardware".
7) both options "Attempt ALL Known security codes in order" & "IGNORE security failure and enter monitor mode".
8) using algorithms "908_GP32.08p" & "908_GP32_Highspeed.08p", ver. 1.10 & 1.03 respectively.

 

All of which produced the same outcome.

 

My suspicion:-
1) Algorithms "908_GP32.08p" & "908_GP32_Highspeed.08p" could be problematic (ver.)?
2) PROG08SZ could be problematic (ver.)?
3) Noise in Vdd (planning to use an LM7805 voltage regulator to produce a clean 5V), but I doubt that's the prob.

 

My uncertainty:-

1) Does it make a difference if I connect (RST)' to either Vdd / GND? I tried both, but it didn't solve my prob.
2) Are there suppose to be circuit changes (disconnecting components, removing wires, etc.) after I enter monitor mode?
3) Are other prog.s suppose to be opened together with PROG08SZ after entering monitor mode such as ICS08GPGTZ?
4) How long does it usually take for each programming func. (blank check, erase, prog. module, etc.) to complete?
5) What confirmations am I suppose to expect when the programming func.s are done?
6) What does it mean when my memory data show "UU" thoughout the Flash memory?

 

Attached with this post are the implemented circuit diag. & pic., & screenshot of the PROG08SZ output.

 

I plan to use a USB-to-RS-232 adapter. I know that the HC908 is not compatible with certain types of adapter chips. Any recommendation on which one I should use & which driver file? It'll be of great convenience for me to use one.

 

Thx.

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Message Edited by t.dowe on 2009-10-19 10:35 AM

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