What It is:

A program that simulates a PIC16F84 microcontroller in an Unix host, featuring:
- Hexadecimal file input.
- A text-mode "graphical" debugger.
- Logic-analizer-like plotting of port A and port B signals. (X11 required)
- Detailed core and peripheral emulation.
- PAL video-game emulation.
- Single pin sound output.

Emulation includes:
- uC Core:
   Pipelined execution: Prefetch, execution, prefech-discard.
   Sleep mode. PortA/B tristate behavior.
- Timer module:
   Prescaler, writing delays, external clock, programmable edge.
- Interrupts:
   Timer Overflow, RB0/INT, programmable INT edge, RB4-7 change.
   Awaking CPU.
- Watchdog timer:
   Nominal 18ms watchdog timer. Prescaler.
- EEprom:
   Writing unlock sequence. Nominal 4ms writing delay.

Things not yet (and maybe never) emulated:
- Open drain in RA4.
- Pull-ups.
- Power-up timer.
- Code protection. (Stupid thing for an emulator/debugger :)
- Oscillator start-up.

Compilation:
- Edit the Makefile file and select your IO interface.
  - set "IO=softvideo.o" for Rickards Guneé video hardware.
  - set "IO=io.o" for a minimal IO skeleton.
  - uncomment "SOUND = -DSOUND" for sound emulation.
- If sound emulation is to be compiled edit the "sound.c" file. Select the
  correct SND_PORT and SND_BIT defines for your hardware.
- Type "make". No non-standard libraries are needed during compilation.
- X11 server is required to display waveforms and video emulation.
- A sound driver is required for sound emulation.

Tested systems:
- Linux-386:	  	Development platform. gcc-2.95.3 generates a buggy
			code. Use gcc-3.0.x instead.
- Solaris-sparc:  	GNU tools OK. Use rxvt color terminal. Sound not
			yet tested.
- Digital-unix-alpha:	GNU tools OK. Tested on a remote machine: X11
			behavior not known. No sound.

To do:
- External world interfaces. There are a lot of different hardware that can
  be attached to this microcontroller. I'm thinking about some sort of 
  plug-in code.

Never to do:
- Windows port.

Bugs:
- Probably a lot. Do not use this code to control a nuclear reactor! 
- Bug reports are welcome, but do not expect a fast patched revision. Here
  is the code. You can patch it yourself.

Copying:
- This PIC16F84 emulator for Linux/unices is distributed under the GNU GPL
  license.

About Author: Jesus Arias
- E-mail: jesus@ele.uva.es
- Web:	http://www.ele.uva.es/~jesus
- small-bio:
    spanish, 36 years, single. University professor. Electronics engeneering.
    Analog IC design. Computer fanatic since Apple ][ days.