gnupic: PIC VM and PIC-on-PIC emulation
Subject:
Re: PIC VM and PIC-on-PIC emulation
From:
"George M. Gallant" ####@####.####
Date:
24 Dec 2004 13:55:36 +0000
Message-Id: <41CC1FBC.2080801@comcast.net>
David,
Try the pic18f252. It is pin compatible with the 16f876. 40MHz, 32K byte
instruction, 1536 byte ram, 31 stack depth. Like
a breathe of fresh air after the confines of the 876. I even run a
multi-tasking scheduler. Supported by gputils and SDCC.
George
David McNab wrote:
> Hi,
>
> Has anyone written a PIC16Fxxx emulator to run on PIC16Fxxx?
>
> If so, does it support execution of programs residing off-chip, say,
> in 24LCxxx I2C Serial EEPROM?
>
> And if so, would gpasm or other tools allow assembling of programs
> larger than the PIC 16F876/7 8kword limit?
>
> I ask, because I'm experimenting with an on-PIC VM which executes code
> resident off-chip within I2C serial EEPROM (24LC256 presently).
>
> This VM is an escape from PIC hardware limitations (eg 8k program size
> and 8 return stack). This VM allows n return stack levels and up to
> 64k code size.
>
> (Also, the VM contains a bootloader which downloads bytecode program
> images and writes them to I2C EEPROM. And, I've got a basic Forth
> compiler working which generates bytecode images for the VM).
>
> While writing the VM, it occurred to me that a PIC-on-PIC emulator
> might also work as an escape from hardware limits - provided that
> compilers can be persuaded to support access to 64k program space.
>
> So if anyone has already written a PIC-on-PIC VM, I'd like to know, so
> I don't go reinventing any wheels.
>
