USBtiny can't communicate with Atmega8515

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

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steuerm
 
Posts: 2
Joined: Mon Nov 28, 2011 10:27 pm

USBtiny can't communicate with Atmega8515

Post by steuerm »

Hey there,

So, I'm attempting to communicate with my Atmega8515 via avrdude. I'm using the 6-pin ISP connection from my usbtiny kit that I've assembled. The standard 6 pin pinout confuses me but I am almost sure that I have the correct pinout from the usbtiny programmer to their corresponding pins on the 8515. The cable I have came with the usbtiny kit. The cables are 1-to-1, so as long as pin 1 (red wire) goes to the red wire on the other side of the ribbon cable, I should be good.

Avrdude recognizes the programmer, and I'm measuring 5 volts to the chip via the programmer power supply.

I'm getting "avrdude: initialization failed, rc=-1. Double check connections and try again."

I am using a basic breadboard and hard wiring the proper 6 control pins on the 8515 with my 6 pin ISP from the usbtiny.

Do I have to initialize anything on the chip prior to testing the connection via avrdude? I'm doing this right out of the box so to speak, as my 8515 arrived from Digikey yesterday. I've read up on in circuit programming and it seems like the process is a bit more complex, but I am assuming that avrdude executes the necessary pulses and what not to get the MCU initialized.

For testing, I'm typing the following on the CMD prompt: avrdude -c usbtiny -p m8515
1.PNG
1.PNG (31.85 KiB) Viewed 1534 times
Any thoughts? I've copied some code from the Atmega8515 datasheet...

Thanks!


The following code examples show how to initialize the SPI as a Slave and how to perform
a simple reception.

void SPI_SlaveInit(void)
{
/* Set MISO output, all others input */
DDR_SPI = (1<<DD_MISO);
/* Enable SPI */
SPCR = (1<<SPE);
}
char SPI_SlaveReceive(void)
{
/* Wait for reception complete */
while(!(SPSR & (1<<SPIF)))
;
/* Return data register */
return SPDR;
}

steuerm
 
Posts: 2
Joined: Mon Nov 28, 2011 10:27 pm

Re: USBtiny can't communicate with Atmega8515

Post by steuerm »

UPDATE:

1) I had incorrectly placed R7 instead of R6. I removed R7 and placed R6 (same resistor). My results were the same after this.

2) I added jumpers for R4 and R7 as the forums suggest. My programmer now seems to work, as I am getting a positive reading via avrdude including device signature.

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