I was wondering if it was possible to redefine the reset pin? I would like to have the 3x2 SPI header to include Slave Select instead of Reset, removing the need for a separare SS connection from the Arduino to the circuit (in addition to the 3x2).
Thanks.
Because you have not told us what Arduino you have, it may be difficult to answer. On an Uno, the reset pin can NOT be reassigned as an Arduino pin, but it may be used also as bit 6 on port C.
I do have an Uno.
vaj4088:
... it may be used also as bit 6 on port C.
I don't understand how I would access that. Can it be an output, and used as SS?
In the datasheet
• RESET/PCINT14 – Port C, Bit 6
RESET, Reset pin: When the RSTDISBL Fuse is programmed, this pin functions as a normal I/O pin, and the part will have to rely on Power-on Reset and Brown-out Reset as its reset sources. When the RSTDISBL Fuse is unprogrammed, the reset circuitry is connected to the pin, and the pin can not be used as an I/O pin.
I have never needed to change fuse settings before, but I am sure there are plenty of tutorials out there. If you need to know the fuse settings, then you can google "avr fuse calculator" and get a website like THIS. After I selected the RSTDISBL bit, I end up with this...
-U lfuse:w:0x62:m -U hfuse:w:0x59:m -U efuse:w:0xff:m
maybe somebody can help with the final step(s).
Great! Thanks!
Sorry, but I couldn't get it working. Any further suggestions?
Feddar:
Sorry, but I couldn't get it working. Any further suggestions?
Tell us what you did?
I tried to figure out how to use the code
-U lfuse:w:0x62:m -U hfuse:w:0x59:m -U efuse:w:0xff:m
But I could not. I'm totally stumped.
Do a google search for "AVRDude Arduino fuse settings"
I've looked around. Still stumped.
Once the fuse is reset, using the command above, how do I access the old Reset pin on the SPI 3x2, as an output Slave Select pin?
If you use the fuses to redefine the RESET pin as GPIO, you won't be able to load software onto your Arduino any more...
Good to know. Doesnt sound like a good idea...