Traditional rc=-1 with atmega128..

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
sarkkas
 
Posts: 4
Joined: Sun Feb 03, 2008 4:28 am

Traditional rc=-1 with atmega128..

Post by sarkkas »

I just can't get things to work. I have already gotten the interface to work with a different (also self-made) project, so I know that the USBtiny works. The atmega128 is brand new, so there shouldn't be any fuses or other programmer-related errors regarding MCU settings.

I have looked through all of the VCC and AVCC pins and all get a stable 5.06 V and all are equipped with 100nF caps. Reset is held high from VCC via a 10k resistor, by the book. 8 MHz crystal attached between XTAL1 & XTAL2 with grounding caps (22 pF) on each leg. AREF grounded via cap. When I try sudo avrdude -c usbtiny -p m128, I get a flicker on RESET and some changes are also visible on SCK. (I'm using a Fluke 77 multimeter to check things out for now, but tomorrow I'll have a scope to probe the board with.)

I've heard varying rumours regarding the PEN pin - that some say it should be grounded and others say it should be pulled to VCC. Many just leave it be.

All ISP connections have been traced from the legs of the MCU to the port on the board and all are fine. I opened the USBtinyISP case also to verify, that the 6-pin header is getting the same signals as the 10-pin header, as my previous project (that worked) used the 6-pin connector, but this one is using the 10-pin header.

What's next? How should I advance with the project?


-Sale

pepper_bg
 
Posts: 2
Joined: Sun Mar 09, 2008 1:12 am

Post by pepper_bg »

I see the same thing. I can read/write from/to a attiny45 (self made board) and atmega168 (the boardino) but rc=1 from the atmega128 (a standard Wiring board which works fine). The only difference I see is that those which I get to work use the 6 pin connector while the one with the atmega128 uses the 10 pin connector, which may not mean much anyways...

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »

i dont have any boards with a '128 :(
but try this:
http://ladyada.net/forums/viewtopic.php?t=5342

User avatar
sarkkas
 
Posts: 4
Joined: Sun Feb 03, 2008 4:28 am

Post by sarkkas »

Yeah, the problem was solved. Once again, it was a case of RTFM. The Atmega128's MISO and MOSI pins aren't the pins that I should have been using for ISP connections. Connections to Port E at the suitable points (PDI/PDO if I recall correctly) solved the problem.


-Sale

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »


pepper_bg
 
Posts: 2
Joined: Sun Mar 09, 2008 1:12 am

Post by pepper_bg »

Just to follow up... So I tried what's in http://ladyada.net/forums/viewtopic.php?t=5342, but neither short-ing the two resistors nor the IC pins changed anything (BTW the programmer kept working with my other non-atmega128 boards). Compared the ISP 6 and 10 pins and they match. Followed the connections all the way from inside the usbtiny to the pins of the atmega128 and they seem to be OK. Asked at the Wiring forum but didn't get much there...

Thanks for your help...

Locked
Please be positive and constructive with your questions and comments.

Return to “USBtinyISP”