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Rotary encoders external pullup
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Rotary encoders external pullup

by djsf on Mon Jan 21, 2019 5:37 am

I've almostly completed building my x0xb0x, everything but the VCF works. After building the digital part and programming the MCU (firmware/x0xb0x.hex from CVS repo, hfuse=0x99, lfuse=0xEE), the sequencer behave strangely switching from mode to mode. Spent several hours reprogramming firmware/playing with fuse settings/trying external oscillator for the MCU, then checked rotary encoders with the ohmmeter.... OMFG!!! Open switch resistance was about 40kOhm! Definitely too low for Atmega pullup (20-50k) to be effective. Then I connected 4 5k pullup resistors to MCU pins 34-37, and now both encoders work ok!

Original Grayhill 25LB22-H encoders are used.

djsf
 
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Re: Rotary encoders external pullup

by antto on Mon Jan 21, 2019 2:01 pm

btw, you'd want to program the bootloader onto the chip
then use the bootloader with a computer to program the firmware
it's also possible to make a "combined" .hex containing both the bootloader and a firmware, and flash it at one go, but that's tricky
i'd suggest you flash the bootloader

antto
 
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