Display issue- trimpot? [solved]

Discontinued products Shruthi
#1

Today I finished my Shruthi build and flashed the MCU with a Sparkfun USBtiny AVR programmer and AVRdude. The LEDs work, I’m able to click different ones on by holding for a second, the LFO blinks and I can change the rate. There were no errors while bootstrapping and all relevant pins (31-39?) are continuous with their header pin for the LCD. I haven’t loaded the eeprom so the encoder doesn’t change the LEDs. I wondered if this could be a trimpot issue since I first populated it with a 20k for the filterboard, wasn’t able to remove the ground pin from the hole when removing it, and just bent the Bourns 3296 5k leg, soldering to the old pin but the pot had no effect and I took it out after realizing it wasn’t connecting right: When I connect the ground terminal (lowest of the 3) directly to LCD pin 3 the 1 filled row/1 blank row appears at full brightness, and I can bridge this (or the lower two pot holes) together with different resistors for brightness (750-1k seems a good range) but even when I add a 5k across from top to bottom ( which is +5v to ground?) the display doesn’t work properly. I do notice that pin 31 of the Atmega is continuous with the +5v, not sure if that’s supposed to be? I’m also not getting sound but I can’t verify that the unit is receiving MIDI, I could just be sending on the wrong channel because I’m not all that familiar with the keyboard I’m using. If I handle the filter board certain shorts do create audible tones. What else can I check?

Thanks in advance!
Johnny

#2

Hmmm are you sure you set the fuses?

#3

Hi, thanks for responding. I tried to, with this command you mentioned: ‘avrdude -c usbtiny -p m644p make bake_all’ and it didn’t say anything, just gave me another prompt so I assumed it worked but in hindsight maybe not. Then I sent ‘… -U flash:w:shruthi1_1.02.hex’. I’m completely inexperienced with this digital stuff so honestly I’m not sure about anything.

#4

I searched for ‘set fuses’ and found these commands:

#avrdude -V -p m644p -c bascom -P /dev/ppi0 -e -B 10 -U efuse:w:0xFD:m -U hfuse:w:0xD6:m -U lfuse:w:0xFF:m

#avrdude -V -p m644p -c bascom -P /dev/ppi0 -e -B 1 -U flash:w:shruthi1_0.97.hex:i -U flash:w:muboot.hex:i -U eeprom:w:internal_eeprom.hex:i -U lock:w:0x2f:m

Obviously I need to change the programmer, port and .hex file but are these basically correct?

edit: it seems like they must be, I see the splash page and menus now. Thanks, I don’t have a clue about AVRISP programming and that sent me in the right direction