Hi,
Could anyone give me AVR source code to implement SPI by software? I need it because I want to have SPI and also external interrupt on ATTiny22. But the pins are overlapped if the two functions are used.
Thanks!
Software SPI
Nov 15, 2004
6 Replies
Atmel has an app. note with software SPI receive. I modified it for transmit using a '2313, and it worked fine, communicating with a PIC with hardware SPI.
Leon
Leon Heller, G1HSM
http://www.geocities.com/leon_heller
Sorry, that should read SPI master instead of SPI receive. I actually modified it for slave operation, with a PIC SPI master.
Leon
Please note that a software SPI slave is in a very difficult timing position: all transfers are timed solely by the master and the slave must be fast enough to keep up, This will usually mean thet the slave has to use most of the processing time polling the SPI clock.
Tauno Voipio
tauno voipio (at) iki fi
Polling? Why not interrupt-on-change?
Thanks!
Probably because the original poster wanted to use the interrupt for something else. Sound like he needs to rethink the problem.
Peter
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required