MicroSquirt.com read only forum (Jan.15,2018)

Having a pretty good problem with a new Microsquirt. I am getting no comm at all with it. I am using a USB to serial adapter that works well with a MS2 v3 setup that I have. I am now on my second Microsquirt, same issue. The guys at DIYAutotune have been great in trying to help me, but perhaps I can get some help here, and get this resolved, too.

More background. Last uS would not talk to the PC. I have the harness here on the bench, feeding nothing but power (13.6v from a power supply, red wire and three black grounds hooked up) to it. No other wires hooked up, beyond the serial port. With both uS boxes, I am getting 5v on the VREF line, so the regulator is happy. I took the first uS apart, and probed all the way back to the processor to be sure that the RS232 signal were getting through. It would not connect to Megatune, would not show up in Portcheck, and I could not download code to it. I sent it back to DIYAutotune. They said it appeared OK, but had no code on it. Got this box from them, and it all appears exactly the same. I hooked a serial protocol analyzer between the PC and the uS. All communications are one way only, except when I turn the power supply off, I get a few random garbage bytes from the uS. I have not taken it apart yet, but all outside indications are that it is in the same boat as the last one. Is it possible that these boxes are making it out the door with no code on them? Would that cause the bootloader to not work? I have verified that TX and RX are good all the way to the end of the harness (did a loopback test). Again, this same setup talks to a MSII, no issues at all. Any thoughts? I am a EE type, so I have the skills and the tools to do pretty much anything that needs to be done/tested/tried. Thanks in advance for any help!

I'm currently connecting my uS(V2) with my notebook via USB-Serial adapter. That's works fine.

When I setup the comm. with uS, I need to set OFF the FIFO buffer of the COM port setting.

OK, just went into the settings for my USB cable, and no luck. Thank you for the suggestion. Keep them coming!

Email me offline at bbowling@earthlink.net, I will try to assist. Since two boxes act exactly the same I would suspect the harness.

All microsquirts get tested before they are released.

- Bruce

Email'd you.

OK, spent several hours today troubleshooting my uS. Here's what I've got. The MAX3221 chip is shot. The Rx side seems to work, but the Tx side does not, and the chip gets hot. While troubleshooting, I pulled out and old RS232 -> TTL interface board I have, and hooked it up. Well, that actually fixed it. It's all talking now! Just need a new MAX3221 chip, and I should be all set!

Hi.I'm a newbie to all this and have been pulling my hair out with the same problem.I had some initial success with the uS but then uploaded the trigger checker programme to satisfy myself the cam trig timing...great...no probs.Then I tried to re-load code and found that I could no longer comunicate with the uS.The downloader prog says that code has been installed succesfully although MT and portchecker will not see the uS.I have checked continuity on cables(and by-passed audio jack),port settings and had a look and sniff in the box.The only possibility I thought I could find was an apparent lack of track to the TxOut pin but surely that can't be possible?

After reading this;

1)Do you think I have the same problem as the previous post?

2)Could it have been caused by something I did?

3)Is there anywhere in the UK to get it tested?

4)Can it be economically repaired?

Any help would be greatfully appreciated and thanks in advance.

It could be, but also check which USB-> serial cable you are using. I have found on another uS that it was VERY picky about what cable I needed to use. I ended up having to spring for the high dollar cable, and everything worked fine.

Thanks Niel.I'll try reterminating the existing cable with a new DB9 but I doubt it will work as the cable bells out OK and 'wiggling'the connectors produced no results.ANYTHING is worth a try before resulting to invasive brutallity!! Cheers.

soapy wrote: 3)Is there anywhere in the UK to get it tested?

PM me with a phone number and I'll talk you through it if you want...