coarse evaluation before buying PIC18F452 or PIC18F4685

Parts Questions
1

hello all of you,

firstly, I have to thank you before anything.

you produced and produce a very big framework with a very nice community.

I read a lot, I’ll continue to do that to be more aware.

But At this point (just before to buy) I need some help. I just hope you won’t find my question as a very newbie question and that it won’t disturb you…

I read http://www.midibox.org/dokuwiki/doku.php?id=mios_pic18f4685 about PIC18f4685

indeed, when I read http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en026324 and http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010297 , I can see the differencies between them about internal EEPROM, internal flash and RAM.

I read that MIDIO128 (128 buttons + 128 leds) is very ok with  PIC18F452

I only produce and receive midi messages, no sound (no chip for that in the box!)

My project will involved 98 buttons, 103 pots and 90 RGB leds.

I’ll use 2 core +

4 AINx4 for pots

3 DINx4 for buttons

2 DOUTx4 (one for multiplexing 8x8 rgb leds with 2 Darlington Transistor Arrays, the other one for the same kind of matrix, but smaller i.e 8x3 + 2..)

1 LTC

do you think I’ll need PIC18F452 or PIC18F4685 ?

I read that modification in os and app could it be required to use the PIC18F4685 (http://www.midibox.org/dokuwiki/doku.php?id=using_pic18f4685 : “Note: PIC18F4685 and PIC18F4682 are not 100% binary compatible to PIC18F452. RAM from 0×60-0x7f is not directly accessible. BANKED accesses have to be used instead.”)

I hope I’ll find infos about that :slight_smile:

long life to the community

ps: my project will be published asap and ALL will be available (code/schematics/design/photos)

2

Am I allowed to choose “neither”? :slight_smile: I’d say you want 4620. More RAM than a 452, which will be handy for your app, and still a little bit more than a 4685. 4685 is only really needed if you want CAN buss for some reason.

3

hi stryd_one,

sorry, I didn’t check this thread and see your answer.

thanks for your answer.

I’ll get 2 pic 4620!

the project involves a rgb led matrix we’re discussing here, if you’re interested too:

http://www.midibox.org/forum/index.php/topic,12786.30.html

cheers!