I recently bought two attiny85 and an usbasp programmer. Everything worked fine programming them using winavr, but after using Arduino IDE for a while, each one of them stopped working. The attinys are no longer recognized by avrdude.
Is there anything I can do to make them work again?
P.S. I haven't messed around with the clock, I only used the internal 1MHz, so I don't think there is any problem with the fuses.
Would you provide the make/model of the usbasp programmer and with code-tags copy and paste the error message from avrdude? It may shed some light on what is happening.
Tks
Ray
How are you connecting the ATtiny85 to the USBAsp? I've found the communication between a programmer and t85 can be unreliable when no resistors are used on the data lines. Going from memory I think I needed to put a 1k resistor in series on MISO for consistent communication, and I may have even needed one on SCK. I'm pretty sure I had no problems with a direct connection on MOSI.
This is where I bought usbasp from [link], and I've attached to this post an image of the error from avrdude.
@ralphd I think this is where my mistake was. I haven't used any resistors. I used direct connection between USBAsp and ATtiny.
Vlad, I tried programming one of my ATTiny85's on a breadboard with this USBAsp:
http://www.fasttech.com/products/0/10000022/1002900-atmegaattiny-51-avr-isp-usbasp-usb-programmer-down
It worked a few times without any resistors. I think it was with my parallel port programmer that I needed the resistors, though still think it's worth trying with resistors and your USBAsp.
A trick I use when testing is to use a USB-TTL adapter to monitor a line by connecting it to the Rx line. When the line goes low, the Rx LED on the TTL adapter lights up - you could use it to see if the USBAsp is sending data on the MOSI line and to check for pulses on the SCK line.
The best thing is if you have a logic analyzer or scope. I picked up a Saleae clone on aliexpress for <$10.
For now, I'm just waiting for a few days to receive my new order of ATTinys and I'll try using 1k resistance.
About checking if the USBasp is sending data, I think I would just use two LEDs, it's easier than using an oscilloscope.
I re-tested my USBAsp and ATtiny85 on a breadboard. I plugged the top row of the ribbon cable into a 5-pin male header on my breadboard. The pinout on mine is:
1 - MOSI
3 - GND
5 - /RST
7 - SCK
9 - MISO
I plugged a wire into pin 2 of the cable header (Vcc) and plugged that into my breadboard row for pin 8 of my Tiny85, and jumpered the rest of the wires to the appropriate pins (you apparently know the right ones if it was working for you at one point). I did a number of tests, all without any resistors, and didn't have any problems. Given that it worked for you before, either something has failed, or it could be a loose connection. I'd double check the connections with a multimeter, checking for continuity between pin 1 on the USBASP (where it's soldered to the board) with pin 5 (MOSI) of the ATTiny 85, and check them all.
k7vlad:
P.S. I haven't messed around with the clock, I only used the internal 1MHz, so I don't think there is any problem with the fuses.
Is there any chance the fuses could have been written to and changed?
If they are set to expect an external clock then you could try connecting a crystal/resonator or use ArduinoISP2 and an UNO to try programming them again.
If it is a fuse problem then there is also the chance you have disabled the reset pin so the device cannot be reset to enter programming mode. If this is the case then look to build a high voltage programmer to re-program the fuses.
Adafruit has a project to make a programmer from a Protoboard and an Uno. I built it, modified the Protoboard connector to connect to any 6 pin ISP connector and never looked back... The original Adafruit article programs 328's but with a little imagination I got it to program 84's and 85's in the Zif socket and wired the Protoboard ISP connector to the 6 pins used to program the controller and now I can program anything that has a 6 pin ISP connector... Except probably a Due.
Nick Gammon has a very nice write-up on ISP programming that should be a mandatory read for those interested in 'rolling their own'. Located Here Gammon Forum : Electronics : Microprocessors : How to make an Arduino-compatible minimal board.
The overview into the Adafruit tutorial is here: Overview | Standalone AVR Chip Programmer | Adafruit Learning System
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