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Old 01-11-2008, 05:05 PM   #1
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Default Communications Problems

So I just got my MS put together, and I'm having trouble getting it to talk to my computer. I think the issue may be one of power.

When i boot the megasquirt with the boot jumper in place, it seems to work fine. My power supply says its pulling 73mA (should be fine), and I'm able to flash it using MS Download. I've also gone through the communication check using hyperterminal, and that works fine. See below

MegaSquirt Download 2.00

Reading C:/Program Files/MegaSquirt/EFI/msns-extra_mod.s19:
Detected MS-I (HC908) code.
Entry point: 0x0000
Code range : 0x8138-0xfffe
File read successfully.

Opened comm port 1 at 9600.
Wake up attempted:
Wakeup successful.

Erasing:
Erased.

Writing:
Write complete, 1759 records, 27788 bytes.

Verifying:
Signature: S - what?
Boot>
Verify complete.
Elapsed time: 85.11 seconds
MegaSquirt Download 2.00

Reading C:/Program Files/MegaSquirt/EFI/msns-extra_mod.s19:
Detected MS-I (HC908) code.
Entry point: 0x0000
Code range : 0x8138-0xfffe
File read successfully.

Opened comm port 1 at 9600.
Wake up attempted:
Wakeup successful.

Erasing:
Erased.

Writing:
Write complete, 1759 records, 27788 bytes.

Verifying:
Signature:
Verify complete.
Elapsed time: 83.05 seconds

When I boot the megasquirt without the boot jumper wierd things start to happen. On the stim, I1 I2, PMP, and IDL flash at about 4 or 5 Hz, but IG doesn't flash at all. The power supply I'm running it on will do 1 amp which I figured should be more than enough while using the stim. However, about once a second current limiting kicks on. I have a feeling that something is shorting out when one of the transistors switches on, and that this is causing the processor to reset. Changing the RPM **** doesn't do anything to affect the output. When I try to connect to it in Megatune it doesn't see it

When I built the board I went ahead and installed all of the components except for D1, D2 (both are jumped), and Q16. I've also completed the mods on the bottom side of the board. Any idea what might be wrong? Should I remove the extra components?

Thanks for the help guys. I can post pics later if it would help. Just let me know what you need to see.
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Old 01-11-2008, 05:40 PM   #2
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looks like it worked the first time.

try it again using easy therm to upload. i was having problems the other day with MSii downloader.
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Old 01-11-2008, 06:49 PM   #3
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Easytherm worked, but I'm still having the same trouble with the processor reseting. I can't find any bridged solder connections. I'm going to let it run and see if anything gets warm.
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Old 01-11-2008, 07:02 PM   #4
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clean your grounds.

make sure you're running non-inverted spark with my spark mod writeup.
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Old 01-11-2008, 11:51 PM   #5
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I think I found the problem. It seems I accidentally switched the direction of D5. I'm going to go ahead and guess that that its allowing one of the outputs to short to ground. I'll switch it around and let you guys know if that fixes it.
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Old 01-14-2008, 09:17 AM   #6
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Yep I was right. D5 being reversed was causing it to short to ground. I switched it this morning and it worked the first time I plugged it in to the computer (almost). Megatune shows everything except for the RPM. I have all of the tach stuff jumpered as shown in the guide thread. I'll take a scope to it tonight and hopefully get it worked out (unless you guys have any other suggestions).

Thanks for the help
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Old 01-14-2008, 01:56 PM   #7
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If you've done the miata mods you won't get an RPM signal using the regular stim.
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Old 01-14-2008, 01:58 PM   #8
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you can though... you need to use "stim for wheel" in megatune and replace R4 with a different resistor....

Quote:
Originally Posted by Matt Cramer View Post
The Miata mods don't work too well with the V2.1 and V2.2 Stims, which are recognizable by having a row of 5 LEDs instead of four LEDs arranged in a rectangle like the older designs. However, it's sometimes possible to make it work if you replace the Stim's R4 resistor with a 180 to 200 ohm, 1 watt resistor. The resistor gets hot but it works for us.

it works for me
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Old 01-14-2008, 11:13 PM   #9
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Oh well then sweet action my MS probably works. I'll have the harness built in a few days, and should have my car running on it by the weekend.
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