Been looking at Coding Badly's TinyISP. Brilliant work. I would very much like to use the Serial Relay mode in a project with a Mega2560 as ISP and an ATTINY 84 or 2313. The setup file looks like it only configures for the Uno. Is there an easy way to get TinyISP to work with the MEGA? Please advise.
The first step is to assign functions to pins.
Which Mega 2560 pins are used for programming the ATtiny84? (Which pins are the SPI pins?)
What of Nick Gammons ISP Programming Cable with the breakout?
Here http://www.gammon.com.au/forum/bbshowpost.php?bbsubject_id=11635
Doc
(MOSI) D51
(MISO) D50
(SCK) D52
Everything except SS.
Mucking ahead, we also need pin assignments for...
• LED_PIN - the status LED
• The tuning signal (has to be a timer output pin)
• TICK_TOCK_PIN - has to be an Input Capture pin (if there is one)
MISO is used for Serial Relay and Knock-Bang. It may make more sense to move Serial Relay to one of the USARTs.
There is a compile-time switch to move Knock-Bang to another pin so it does not conflict with MISO. We need to decide which alternate pin to use. The alternate pin has to support Pin Change Interrupts. Something physically close to the SPI pins is handy.