My plan is to install v3.3 on a Porsche 944 -83. My idea is to place the the genboard in a empty motronic box and use as much as possible of the original wire harness. I guess one of the bigger problem I will have to deal with is the trigger system with 2 VR-sensors, one keeping track of the referens point and one counting the 130 teeth on the starter gear. I understand it is a version of the "auditrigger".
The parts has arrived and everythings looks fine. Delivery was very quick! :)
Problem is probably solved! :) I replaced the xtal before I checked my mail and this page and that seems to have solved the problem. I made some comments below.
Serial cable and power cable has been attached to the board for some initial testing before soldering more parts to the board. The only problem is that it does not work the way it should.
Strange, because boards go through testing, during which all the supplies (7 or 8 including the max232 -8V), the ISP, the serial communication, the WBO2 pump circuit is tested.
- the Mega128 seams more or less dead (no signal at the x-tal). how do you measure the signal? The impedance of the measurement device can stop the xtal oscillation. However, you can try to heat the xtal solder. I used my oscilloscope and a 10:1 probe so I don't think the impedance was a problem since I have used it before with other chips. Heating up the xtal solder didn't help.
- often it takes half an hour before it starts up so you can get some communication with a terminal program. Manmll command works fine (this is impossible without
- but Megatune can not connect to the board. don't forget to leave "Man" mode (if you entered) by issuing the "bye" command. I rebooted the card after switching to Megatune
Once you get it starting it will stay alive until you remove power for a few minutes. 5V supply is always okay and the reset signal goes to high every time you apply power.
- My next idea was using ISP cable and BASCOM-AVR to connect to the chip and see if BASCOM's 'identify chip' function worked. It did not, BASCOM didn't get any data from the chip. BASCOM and the cable worked fine with a Mega88 chip both before and after my test.
- Are you aware that the atmega128 has the PDI, PDO in the ISP interface (not MOSI, MISO) ? Acording to the schematic MOSI and MISO should be found at pin 7 and 8 in the JP_ISPI?
- you can measure all supplies of the AVR (there are a few VCC, AVCC, AREF...)
- measure supply current around 80 mA on first start up (not working)
- write serialNr 351
- inspect the AVR and max232 area visually looks good
Q: What to do next?
- order a new board from WebShop (and optionally a few small parts you like), choose money-order (don't pay, just refer to this site). Keep the "believed to be bad" board in it's current state before we decide about it (either you'll find later it was just something small, or we'll ask you to return later to someone in Sweden or Hungary).
A very nice offer, hopefully I don't need a new board now.