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Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sun Jul 20, 2008 10:34 pmby dmitri
I had a strange issue with one of two PIC18F2550 chips today. USB was working fine with one of the chips but not with another.
The only way to make this chip work was to pull pin 26 of PIC18F2550 to +5 over a 10k-47k resistor. Weird.
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Fri Dec 12, 2008 7:34 pmby dmitri
If you happen to encounter a similar issue try this firmware:
pic18f2550usb_midi.hex
pin 26 should be connected over a 22k-47k resistor to ground instead.
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sat Dec 13, 2008 4:37 pmby Xmattz
Dimitri, stop talking in russian in english section of forum...
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sun Dec 14, 2008 6:14 pmby dmitri
This is the source:
PIC18F2550 USB.zip
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Fri Feb 13, 2009 7:59 pmby dmitri
By now several people have had the same problem I had and all of them confirmed that this PIC18F2550 USB MIDI firmware fixes it, of course, with the required small schematic change (pin 26 should be connected over a 22k-47k resistor to the ground).
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sat Feb 14, 2009 12:04 pmby r0bbie
Hi Dmitri,
Finished my hardware (Synthex) yesterday, and gues what, USB problems.
I found this post this morning and added a 33k pulldown resistor to pin 26.
Problem solved, without updating firmware. should i worry?
Thanks
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sat Feb 14, 2009 12:12 pmby dmitri
If it works - it usually works. Just do a bit longer testing.
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Tue Feb 17, 2009 6:39 pmby NovaKaine
Grrrrrr
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sun Mar 15, 2009 10:38 pmby dmitri
This file contains 5 PIC18F2550 USB MIDI firmware versions for 4/8/12/16/20MHz crystals:
PIC18F2550 USB_4_8_12_16_20MHz.zip
In theory, by using the same frequency firmware for both Atmega and PIC18F2550 it may be possible to use just one crystal instead of two.
Re: Possible issue with some PIC18F2550 samples and a fix.
Posted:
Sun Mar 15, 2009 11:16 pmby Ken Forgettable
dmitri wrote:This file contains 5 PIC18F2550 USB MIDI firmware versions for 4/8/12/16/20MHz crystals:
XMEGA dev'
- just with a change to CLOCK_FREQ in "HardwareProfile - pic18f2550.h" for these then?