Atmega328 (no p) has compile/upload catch-22?

Using Arduino Microcontrollers
1

I have a standalone breadboard with an atmega328 (rather than 328p) on it.
I am using an USBtinyISP to upload to it.
I have configured the IDE in boards.txt to add a new kind of board, with the appropriate fuse bits.
I have added a device called atmega328 to avrdude.conf which is a copy of the 328p, except with a signature of 0x1e 0x95 0x14 instead of 0x1e 0x95 0x0F.

However, I can't figure out how to make the system compile like a 328p, but upload like a 328.
Here's my snippet from board.txt:

##############################################################

standalone328.name=Standalone 328 USBtinyISP
standalone328.upload.using=usbtinyisp
standalone328.upload.maximum_size=32768
standalone328.build.mcu=atmega328p
standalone328.build.f_cpu=16000000L
standalone328.build.core=arduino
standalone328.build.variant=standard
standalone328.bootloader.low_fuses=0xE2
standalone328.bootloader.high_fuses=0xD9
standalone328.bootloader.extended_fuses=0xF5
standalone328.bootloader.path=optiboot
standalone328.bootloader.file=optiboot_atmega328.hex
standalone328.bootloader.unlock_bits=0x3F
standalone328.bootloader.lock_bits=0x0F

The problem is the build.mcu field. When I set it to atmega328p, it tries to call AVRdude with atmega328p, which has the wrong signature bit.
When I change it to atmega328, the compiler complains that it doesn't know about that chip.
I think what I want to do is compile as atmega328p, but upload as atmega328. However, i can't find the right combination of configuration options to make that happen.

Because I'm using the USBtinyISP, is there a configuration option for upload.*** that lets me set the device type to pass to AVRdude?

2

Lie.
Set the build.mcu to m328. Use this boards.txt to "burn bootloader" using the m328p bootloader.
Change the build.mcu back to m328p; the bootloader will happily tell AVRDude that it's a 328p CPU even though it's really just a 328, and all will be happy.

(alternately, leave boards.txt as 328p and use some other mechanism (avrdude, optiloader) to load the 328p bootloader onto the 328...)

3

Find your AVRDude.conf and make sure there is a 328 chip defined. It can be the same as the 328P except for the signature. Once you have a bootloader it will load from Arduino without a problem.

4

That's what I do. I have a target set up in the IDE and avrdude.conf for 328 bootloading, then change the target to a standard Uno to upload a sketch. I upload via serial, not ISP though.

5

westfw:
Lie.
Set the build.mcu to m328. Use this boards.txt to "burn bootloader" using the m328p bootloader.
Change the build.mcu back to m328p; the bootloader will happily tell AVRDude that it's a 328p CPU even though it's really just a 328, and all will be happy.

(alternately, leave boards.txt as 328p and use some other mechanism (avrdude, optiloader) to load the 328p bootloader onto the 328...)

I am not using a bootloader. I am directly programming a stand-alone m328, using direct ISP, and would like to do so through the IDE.
This would work if I could specify a different symbol/model to the compiler than to the uploader. I'm wondering whether there is a way in the config file to do this.
Also, I'm wondering why the compiler recognizes atmega328p, but not atmega328, as a valid target. It recognizes 329, 325, and others without a "p"...

6

if I could specify a different symbol/model to the compiler than to the uploader.

Not that I know of...

I'm wondering why the compiler recognizes atmega328p, but not atmega328, as a valid target.

It's a pretty old version of the compiler. I don't think that there was a separate 328 and 328p sold at the time the compiler was created. (there are other problems with newer versions of the compiler, however. Atmel has said that they'll have a new "package" version of the compiler (winavr) "soon."

7

"Real Soon Now," huh? I know what that means :slight_smile:
I guess I'll just pony up the extra dollar and get 328p parts for now.