I bought 5 ATmega8-16PU at a great price. I put the bootloader in using Nick Gammon's tutorial and software Gammon Forum : Electronics : Microprocessors : Sketch to detect Atmega chip types. I used a MiniPro to install the bootloader. It was easy, the software worked flawlessly and Mr. Gammon's tutorial is great. Thank you, sir.
I hooked up an led to D13 to see if I got the blink. I get about 6 rapid blinks then a delay of about 25 seconds and then it repeats. I don't remember seeing that on new MiniPro boards. Seems to me it was always just steady blinks.
Any way, I could not download with my USB to serial converter. It is a converter I have used hundreds of times on my Uno and also on some MiniPros. Never a problem. I checked everything quadruple times, at least. I then downloaded a sketch on one of them using SPI with my Uno. Worked fine, the sketch runs. Tried the USB converter again, this time using a .1 uf cap as in the turorial instead of the 2 uf it had but still no dice. I get the message stk500_getsync(): not in sync: resp=0x00.
My USB converter is a CP2102 installed on a homemade breakout board with the standard 10k resistor from reset to Vcc and the capacitor from reset to DTR . I also tried several ATMega8 chips that I had installed the bootloader on.
I have to conclude the bootloader is the problem for some reason.
Forgot to mention the ATMega8 setup is on a prototype breadboard and in addition to using the breakout board I also tried plugging the CP2102 directly into the breadboard and plugging in the hookup reset to DTR with the capacitor and the resistor. Always the same result. I am using Arduino NG or older W/ ATmega8 in the IDE. which is the only choice for the 8.
I have to conclude the bootloader is the problem for some reason.
Nick's tool uses the original ATmega8 bootloader (1k in length, etc.) Is that what you have your Board setting and boards.txt set up to use?
(Hmm. The mega8 fuses in Nick's program are a bit suspect; they don't match the old boards.txt, or the bootloader makefile. It looks like they might run using the internal RC clock instead of an external crystal. Try changing LFUSE to 0xDF and HFUSE to 0xCA )
OK, maybe I know where the problem is. I had only looked over the Summary document on the Atmel site and I assumed the internal RC oscillator was running at 16 mHz. I have now looked over the complete document and see the fuse settings are for 1 mHz and the maximum with internal RC is 8 mHz. I can live with 8 mHz but I have to change the CKSEL bits and also, according to what I read on Arduino site, change baud rate in "Arduino Preferences" file, which I cannot find.
Any help making this thing work is appreciated greatly.
Thanks, westfw. Yes, that is the selection I used under Boards menu. I am not using an external crystal. I am running with the internal RC oscillator, which I have recently learned, is set at the plant to 1 mHz; it is little wonder that I cannot communicate using the USB. Now I have to find the easiest (and safest) way to change the fuse setting.
Doesn't Nick's program set the fuses as well as loading the bootloader?
(but the bootloader it's loading is designed for running at 16MHz, whereas I think he sets the fuses for 8MHz internal (which is what you want.)) Try just halving the baudrate in boards.txt?