For the software writing gurus:

As stated in a previous post, I'm working on software for PocketPC for at least the 165 and 730 ECMs.

I've hacked up a cable, damned if I know if it works yet or not. There isn't anything in existence on building a PocketPC compatible data cable - so I don't know if I need to do anything different than a run of the mill USB data cable. And manufacturers aren't too open with their pin-outs.

From what I can tell, the ECM does not respond if I do not send a valid request. Is this correct? If I send an incorrect byte, I get nothing?

Is there anything I can do to find out if the cable itself works? Being that its an ALDL connector on the one end limits me to testing on the computer itself. Any way to get the ECM to just dump so I can play with the cable till the PPC starts receiving?

TIA

 

From what I can tell, the ECM does not respond if I do not send a valid request. Is this correct? If I send an incorrect byte, I get nothing?
Pretty much. ECM won't respond to data that it does not understand.

Any way to get the ECM to just dump so I can play with the cable till the PPC starts receiving?
There are some MaskIDs that will xmit chatter. The $88 ('730) and $58 ('749) are two that do this. You should see the constant chatter coming across.

RBob.

 

Thanks RBob, now I've run into a new issue (hopefully a non-issue):

I've been trying to connect to the ECM with no success. I can't tell if its the cable or not, but the cable hooked up to a laptop worked last I used it (about 6 months ago).

Now, here's the thing: PocketPCs aren't like desktops when it comes to the serial port. The controller can only use predefined rates - and you guessed it, 8192 isn't one of them.

I know with a PC-PC connection if one is set to a rate the other can't handle/doesn't support, it adjusts. Will this work with the ECM? If I set the software to comnicate at 9600, will I be able to communicate with the ECM?

I'm guessing it won't matter as long as I don't go below 8192bps, it'll work, but I'll ask before I go nuts trying just to find out its not possible.

 

The ECM can't change it's baud rate. With the PCs/Laptops we use a UART clock divisor of 14 which gives 8228 baud. Not perfect but good enough to talk to the ECM which is 8192 baud (less than a 1% difference in speed).

RBob.

 

8228 is no good either. At least the iPaq will not allow any user defined speeds. The closest I can get is 9600 with the built-in serial port of the iPaq.

Looks like I'll put this on hold for a bit.