PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

[Lukashenka741]

hm. I tried with an bootloader. sucks. but, when I writed it on ponyprog, programming was successful. Flashed it with MCT but nothing on lcd. I am now watching the ponyprog : I connected megadrum and pressed "READ ALL" so it shows a lot of letters and numbers so its normal, and shows some words like: press key down; sysex send; update finished; erase; ok; and so on. so I presume that my atmega is ~fine... but I CAN'T write the normal firmware file .hex



"EDIT": ha, now done successful write with normal firmware, and readed it like above , however There's still nothing on LCD
somehow I feel that it will be about shorts or breaks

[Lukashenka741]

It still doesn't show anything on LCD... how can I check if my atmega is clocked, and has power?
I measured atmega's pin 9 - 0v... it is reset pin, I suppose that it should be not 0v....

[Lukashenka741]

I've read atmega's datasheet and it say's that reset (pin 9) should be from 0.2v to 0.9v . so according to schematics, resistance between pin 9 and vcc should be 47kohm. it shows me 5k ohm

[dmitri]

You cannot reliably measure resistances in a schematic where semiconductor components are connected.

[Lukashenka741]

so what voltage should be on pin 9? maybe I could do it "manually" like connecting resistor between vcc and pin 9 independently?

[dmitri]

Normally there should be close to +5V on a reset pin.

[Lukashenka741]

hi. I fixed the reset pin. it shows 4.7v now. but still nothing on LCD. PIC working ok. and Ponyprog shows that Atmega contains the firmware code... so atmega is alive, but is not working in the PCB. or it's working but without LCD... have some clues?

[dmitri]

From MegaDrum FAQ. Read it before posting in this forum!:

7. Having LCD problems? Read this topic.

[Lukashenka741]

I have read this before.... does the atmega program without crystal?

[Lukashenka741]

WOW! it worked for a second or two!! I don't know but I done something with programming... I writed bootloader, and then on ponyprog selected program options : erase; write flash; write eeprom; write config bits;
and when programming it showed FW UPDATE 16mhz... then It showed Dmitri Schachkow and it dissapeared.