might be the reason you got it "very cheap".... good luck!
I have a Geodimeter 640 that might still have its firmware intact (I haven't used it in a few years). If you think its firmware might be useful
I'd be willing to attempt the extraction, but I'd need some coaching on procedure.
(Apologies for the formatting, the edit form is acting weird.)
Maybe starting with standard serial communication on GDM600. Here chapter 4.
And maybe this will help:
I have a geodimeter 620, my parameters were Parameters are 9600, 8,n,1. And with CU attached, the command "?" just shows Fimware version "632-09.00" of Control Unit. With CU detached, it shows Firmware version "632-09.00" of GDM620 i think.
The command "DUMP" shows info Code "30" --> Syntax error - Tries to send a command with illegal syntax on the serial channel.
Any other suggestions?
so the command is "OV*" - dump memory,
Other commands are:
"RV,100" - GDM model
"RV,110" - loader time and date
"RV,111"- GDM serial number
"RV,113" - program version
"MR[L]" - read ram, i think that addr needs to be 2 bytes hexadecimal ... "MR2000L2" - should read the checksum (it is located on 2000h address in ram)
"BS[1|2|3|4|5|6|7]" bank select - bank is located at address 0x8000- 0x8080. You can select which bank you want to read with MR.
There are also other programs which i will not list, they are dangerous, - modify ram and load new program (which will erase the old one instantly).
Memory locations are as follows: ( at least on 5500 trimble)
0x2000 - 0x2019 - checksum, program entry point and interrupt vectors are here.
0x2800 - 0x7ff5 - actual program memory.
0x8000-0x8080 - banked data ram.
I only have loader in my 5500. this one is located in ROM inside of the main processor. It will survive battery removal. The loader will check the status of the program memory. If checksums are correct it will jump to the main program immediately.
If none of these commands work, we will have to figure out other means of entering of the loader. (if you short data pins (any two) during turn on, checksums will come up corrupted and loader will be entered, where these commands are working )
loader output looks like this (9600 8n1):
Load new program LV=0
Memory ASCII-hex dump OV*
GDM model RV,100
Link date/time RV,110
GDM serial number RV,111
Program version RV,113
Check RAM CRC CRC
Run loaded program RUN
Power off WV,107=1
Read RAM byte(s): MR
Write RAM byte: MW
Memory bank: BS[1|2|3|4|5|6|7]
List valid commands ?