Hi- I built the MIDIO128, minus the midi out, as I want to MIDI-fy my pipe organ. I cant seem to get it to do anything. I programmed the PIC (16f877) and it verified OK. I power up the board, and some of the output led’s light, but after I send the sysex dump, it still doesnt function correctly. Each time I power it up, different outputs light. Sometimes all then outputs blink on and off about once a second. This is my first MIDI /PIC project, and Im stumped ! Please Help!!!
Ryan
Sounds like a power issue to me.
How hot does the 7805 get?
Whats your Power Supply voltage?
Hi Ryan,
it seems that either the PIC is not powered (did you close all 5 jumper connections at port J3?) or the crystal is not oscillating (check Q1/C1/C2).
Otherwise the PIC would initialize all LEDs connected to the DOUT registers.
Which crystal are you using - part number?
Best Regards, Thorsten.
Hi- Thanks for the replies.
Checked the voltage- no IC’s installed-
5.07 vdc
Installed the PIC and shift registers-
5.07 vdc
The 7805 gets rather warm with all the LEDs on at once, but the output doesnt drop off, so if it cycles them all on, then back off, it should be OK. I can add a heat sink if I need to. Are the LED’s supposed to go back off after they all come on ???
I dont have the plug for on-board programming, and wired the pins of the PIC direct to the associated traces without jumpers. I checked the wiring and all seems OK with the posted schematic.
The crystal I bought from the gentleman where I got the PIC. No number, but it says ‘Stetron, 20.000 MHz’ on it. It came with the caps, and so I would think its the right one for the PIC. I dont have a 'scope here that works, but can borrow one if I need to.
Thanks for the help.
Ryan
If you can still touch the 7805, its absolutely OK. But what input voltage are you using? It could be that its switching off if to much power is drain, so it also wont get warm that way.