i am trying to setup an inchworm+ but i cannot get any programs to connect to the IC. I have tried MPLAB and Tiny PIC bootloader and neither will see the chip i have that came with the kit from blueroom. The PIC is 16F877A. I checked the voltages on the serial port of my computer and i think it is working ok.
I had a problem with the inchworm board originally where the MAX232 chip was pulling excessive current so i replaced it and it seems to be ok now but is it possible the PIC was damaged at this point as well?
so what im wondering is if there a way i could throw the chip on a bread board and take some measurements of something to see if it is functional or not?
i have never had it working so i am not entirely sure it is the chip but i *think* everything else is setup correctly. (yes i disabled the fifo buffer in windows and read and reread the instructions included AND i did a continuity test on every pin of my serial cable, it looks good)
The 16F877A is pretty robust. Do you have a oscilloscope? Is the crystal running?
It takes very little for the communications mode to work. This may seem like a dumb question but do you have access to a PIC programmer? The firmware for the 16F877A can be found in the download section of my site.
hmm no i dont think there is a clock happening. on pin 13 i have a voltage of a bit less than 1 and on 14 about 2 volts on the scope and no square wave.
i do not have access to a pic programmer unfortuantely.
but maybe we have found the problem.
scott.
also yes i have double checked the direction as well but that is always a good suggestion. sometimes i solder sockets in backwards even. and then it looks like the right way but really...
also i dont know if this is relevant but the led beside the clock silk screen (busy) is never on. but i dont know if it should or shouldnt be at any time.
The only time it is on is when the Inchworm+ goes to do something with the attached PIC. So, no it won't be on when you power it up. But the other one should be.
Make sure that pin 1 MCLR is not grounded.
ah ok isee. actually i was wrong about the clock i think. i was thinking i was looking for a nice square wave but i wasn't thinking about that it is a crystal and will be a much smaller wave. which seems to be there.
but your suggestion about pin 1...
when i dont have the serial cable plugged in its 5 volts but when i plug it in it goes to -.7 volts. so maybe my computer port is not ok after all? or is this what should happen?
That is what happens when I rip the Unicorn off and plug it in serial. Powered up by itself pin 1 = 5v. Plug in the serial cable = -.7 or so. Bring up MPLAB and set communications up to serial and connect = 5 v plus, in my case, it decided to download a new OS to it, so the red led lit up.
heres what happens. when i connect with mplab the voltage goes to 5.6 but then fails and i get some error msgs. if i try to connect again manually it just stays low.
umm i tried to post a link to some screen shots but it wont let me post for some reason if i do.
but here is the url i guess copy and paste. it has the corresponding voltage at pin1 in the comments
yes i have been trying to play around with settings for about 2 days. i can get other error msgs like failed to open port as well but never a successful connection. i am using com1. in my bios on the pc the serial port is also set to com1. the serial port shows up in hardware manager.
my motherboard does not have a soldered on db9. it has just pins sticking out for a header. so i have a ribbon cable with a header going to a db9 male panel mount on a pci card bracket type thing. according to the manual i have the header oriented correctly but i have tried reversing it anyways and at that time it didnt seem to be working.
i checked the connection between the header and the panel mount connector for continuity a few days back and it seemed to be ok. maybe tomorrow i iwll go over everything again to be really really sure.
also i read about making a loopback connector to verify the port. i dont knwo how to run a test though but i could definitely make the connector without much trouble.