What do I have to do to be able to use PB6, PB7, PC6 and PC7 as outputs?
PORTD is the only port I've been able to get all 8 LED's to turn on (programming with on the STK500.) On PORTB and PORTC, the 2 MSB's will not change state.
Thanks!
Psychlow 
ATMega48 - PORTB and PORTC only outputting 6 LSB's
Author
Message
Psychlow curtvm PB6 and PB7 are also used for the crystal. Are you using an external crystal?
PC6 is the reset pin- can't use as an output unless you change the fuse (don't do it).
PC7. There is no PC7.
theusch 
You need to do special STK500 cabling to get PB6 and PB7; from the AUX header IIRC. Look at AVRStudio Help; search the Forum for "pb6 pb67 stk500 mega8".
Yes, PC7 >>would<< be a cute trick. And for PC6, then you need to re-cable for HV programming from then on.
Lee
Psychlow Aha - thank you for the info. Yeah, my fault on the PC6/7 thing :).
I wasn't able to find that post, but I did find out the wiring.
PB5:0 wire as usual, of course....
PB6 = XT1, PB7 = XT2 (on the AUX header). With the supplied four 2-wire connectors, there are just enough to get it working.
theusch Quote:
I wasn't able to find that post, but I did find out the wiring.
???
Search found 19 matches AVR Freaks Forum Index Forum Topics Author Replies Views Last Post No new posts AVR forum ATMega48 - PORTB and PORTC only outputting 6 LSB's Psychlow 3 54 Oct 05, 2007 - 09:35 PM Psychlow View latest post No new posts AVR forum ATMega8 pb6 and pb7 voltage level problem [ Goto pageGoto page: 1, 2 ] bnocturnal 22 383 Sep 14, 2007 - 10:32 PM JackFoligie View latest post No new posts AVR forum No ADC on Mega8515 new2use 12 290 Aug 17, 2006 - 01:19 PM dl8dtl View latest post No new posts AVR forum STK500 LED Question pupdawg 2 147 Jun 09, 2006 - 05:54 AM pupdawg View latest post No new posts AVR forum **missing bits on portB [atmega8 & stk500] galazg 4 143 May 24, 2006 - 03:42 PM microcarl View latest post No new posts AVR studio 4 forum mega8: XTAL/TOSC - pins (PB6+7) switch*blade 2 311 Apr 21, 2006 - 02:07 AM switch*blade View latest post No new posts AVR forum ATmega8 PB6 and PB7 Output Issue (ISSUE SOLVED) sjpa 5 244 Apr 13, 2006 - 03:26 PM Bingo600 View latest post No new posts AVR forum LCD no work on Mega8 PortB underwaterreefer 6 139 Mar 14, 2006 - 05:13 PM underwaterreefer View latest post No new posts AVR forum ATMega8 ADC hookup, Help! atellis 4 128 Mar 12, 2006 - 09:07 PM theusch View latest post No new posts AVR forum Atmega8 External RC Oscillator Question eh3 9 289 Feb 20, 2006 - 06:13 AM lfmorrison View latest post No new posts AVR forum How do I use PB6 and PB7 on mega8? Sci 2 222 May 30, 2005 - 05:45 PM CountZero View latest post No new posts AVR forum mega8 PB6,7 I/O problem magno_grail 7 272 Mar 21, 2005 - 06:38 PM theusch View latest post No new posts AVR forum ATMEGA8: Cannot enable Port B6/B7 stefanwurlitzer 7 273 Jan 18, 2005 - 12:52 AM stefanwurlitzer View latest post No new posts AVR forum port problems with an mega8 krazykarl 8 394 Nov 22, 2004 - 01:32 PM mneary View latest post No new posts AVR forum Which microcontroller is the appropriate? Alexandros 12 582 Jul 16, 2004 - 09:29 AM pepsi View latest post No new posts AVR forum Can PB6 and PB7 be used as general IO on a Mega8? Lawrence 3 35 May 28, 2003 - 02:50 AM Sean View latest post No new posts AVR forum PB6 & PB7 on Mega8? StuartWhelan (Stuart Whe 4 77 May 23, 2003 - 04:26 AM StuartWhelan View latest post No new posts AVR forum HELP, mega8 & portb engg100 (Josh Wolf) 9 15 Jan 16, 2003 - 03:29 PM lee View latest post No new posts AVR forum Mega 8 STK500 ISSUE ginvent (Joseph Gottlieb 11 162 Sep 17, 2002 - 08:35 AM lee View latest post