Nismo280zEd Posted December 23, 2005 Share Posted December 23, 2005 So I've been building this board in the wee hours of the morning whenever I get some free time. I pluged in the DB9 (serial) connector to the computer tonight to verify what i have done so far. so I use the hyperterminal like it says jump pins 2&3 on the cable, verify connectivity, it works. Ok so i plug into the board like it says, jump 12&13 on the 40 pin socket like it says. and no connectivity. So i start checking voltage. I trace it back to the serial cable, making me wonder if my motherboard on my computer isn't being gay on me? pin 1 and 9 are supposed to carry a 5v charge correct? I only get like 2.25 -2.35 from pins 2&3. So is it something i did on the board or my computer? (yes i have verified the cable is pass through and checked the voltage coming from the back of my computer (no cable) same thing. Thanks for any help. -Ed Quote Link to comment Share on other sites More sharing options...
tannji Posted December 23, 2005 Share Posted December 23, 2005 Might want to go through your PC bios and verify your serial ports are not disabled or improperly setup. Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 23, 2005 Share Posted December 23, 2005 Let me understand what you are trying to do. You want to loop the serial (RS232) interface at different points in the MS RS232 circuit. So you checked it at the cable, and it was OK. If you can loop at the cable OK, then it is not your computer. You pulled out the processor (U1) and then shorted pins 12 and 13 in the socket. Do you have U6 installed? This translates RS232 levels to TTL (Transistor-Transistor Logic) levels. It is required for this test. Check all components related to U6. Also, if you used a socket for U6, make sure there aren't pins bent under the device (easy to do when installing an IC into a socket). The 5V on pin 9 and 1 of the DB 9 connector are a don't care, as they are probably not connected in your cable. You PC already has a 5V supply in it (and you certainly do not want you MS feeding powering to your PC). Hope this helps, Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 23, 2005 Author Share Posted December 23, 2005 Yes I installed U6 and checked voltages on it last night trying to figure out whats up. Do I need the power supplied on the DB37 connection for the board to test out properly? I'll check the bios I'm going to try my friends computer and make sur its not mine. Should the voltage from pin 2&3 be that low though? Because that's the only power going into my board and from my understand not enough to overcome the diode. -Ed Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 23, 2005 Author Share Posted December 23, 2005 ok it's not pins 2*3 it's pins 3&4 also pin 8 have about 2.35v on them. I'm starting to wonder if I need 12+ to the #37 pin on the other connector to power the board? -Ed Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 23, 2005 Share Posted December 23, 2005 No, you do not need 5V on the DB9 connector. You PC is fine if you can short 2 and 3 of the cable and hyperterminal works. Ed, yes, the MS needs to be powered up for this to work since the 5V that the RS232 chip (U6) needs comes from the 12V. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 23, 2005 Author Share Posted December 23, 2005 Could you do me a big favor? What pin or pins do i supply a 9-12v power to? I've seen the standard schematic on megasquirt site and it does not clearly indicate the power supply, this would be very useful for when I actually wire it into the car as well lol. Thanks alot, I feel really quite small right now with such an obvious question. Thank you again. -Ed Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 24, 2005 Author Share Posted December 24, 2005 so incase anybody else ever has this problem on here. It's pin 28. 12 volt input -Ed Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 24, 2005 Share Posted December 24, 2005 I would suggest getting a stimulator. It is the easiest was to be sure your MS is functioning properly. Best $50 I've spent. It has hookups for power and variable resistors to simulate the different sensors. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted December 24, 2005 Author Share Posted December 24, 2005 unfotunatly I do not have the 50 dollars to spend for a stimulator or the 25-30 in parts to build it. I'm a broke college student working at a hospital trying to make ends meet good sir. Thus is why i'm building the MS myself and the quicker i get it installed and reprogram it the more i start saving on gas. I spend about 60-70 in gas every 10 days. Plus this has to be finished before school starts again in early to mid january. Thank you for the help, I completly overlooked the huge red line coming from the battery. -Ed Quote Link to comment Share on other sites More sharing options...
z-ya Posted December 24, 2005 Share Posted December 24, 2005 Stay in school and work hard, it will pay off in the long run! Quote Link to comment Share on other sites More sharing options...
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