No communication with computer

[rrodriguez]

Hello all,

I'm having troubles with connecting the Megasquirt II V3.0 (Bowling and Grippo blue board) to any computer. I have tried both USB to DB9 adapter and a straight through DB9 cable, both with no luck. I did have to replace the MAX232 chip with one off of another MSII (same version) which solved connectivity issues when doing the loop back test with the hyper terminal. I followed this guide http://www.megamanual.com/connect.htm all the way through with no help. MS downloader says there is a connection issue when I try to flash the daughter card. (jumper in place) I get this in the MS downloader window:

Opened comm port 4 at 115200.
ERROR: Timed out reading response, 0xE0
Elapsed time: 15.04 seconds

Port check won't find the Megasquirt either.
When I connect the db9 cable, all 3 LEDs light up.
When I use the stim the fuel pump and FIdle LEDs light up also when connected to the DB9 cable
For a power source I am using a good car battery with 12.5V
I have checked all powers and grounds the MAX232 chip and to the daughter board.
I have checked the resistance between the MAX232 chip and pins 12 and 13 going to the daughter board. Both with less than 1OHM of resistance.
I have checked the power supply voltages (12V at the left pin, 5V at the right pin)
Is it possible that the processor is bad or is there some other thing that I am missing here?

[kjones6039]

Do I understand correctly that the loop back (at the 40 pin socket) test does work?

Ken

[rrodriguez]

Yes it does work at the 40 pin socket.

[kjones6039]

Yes it does work at the 40 pin socket.

Hmmmmm...... That does raise concerns regarding the daughter card, IMO!

Probably better to wait and see what the experts say though.......

Ken

[rrodriguez]

Yeah hopefully someone can chime in!
It would suck to have to buy a new daughterboard.
Thanks for the reply!

[trakkies]

What was the cause of the MAX232 failure? Just wondering if the same reason could apply to the daughter board?

[rrodriguez]

What was the cause of the MAX232 failure? Just wondering if the same reason could apply to the daughter board?

Not sure, I was handed this MS for a project and as far as I know the MS has never wanted to connect to the computer.
I started going through the testing procedures and found the dead MAX232.

[kjones6039]

I know it might seem redundant, but just to be certain that everything is covered......

Have you confirmed that all voltages at the 40 pin dip are present and the correct values?

Ken

[rrodriguez]

I know it might seem redundant, but just to be certain that everything is covered......

Have you confirmed that all voltages at the 40 pin dip are present and the correct values?

Ken

Just tested everything again and yes 5V all across the 40pin socket(on the correct pins of course). Loop back test checks out again.