I love using pic chips, ive got a pic start development system which i bought some 13 years ago. I write in assembler or C, on a pc, and compile the code into a hex file to send to the programmer. I made a weather station for my electronics project when i was doing my 2nd yr of a HND in electronics a brighton uni back in 1995. Ive also made a midi interface box, but not might change it and turn it into a maths co processor.

Ive started to write the code for my maths co processor now, it works over a serial type interface which is the existing midi hardware, still i can increase the baud rate to 500kbs a second. Quite fast for a data link in 8 bit computer terms. The operation of the box involves connecting it to another host computer to send a command to select the type of calculation to be done. Followed by the numbers to use. The result is sent back to the host computer. This frees up the host computer to do something else while the co processor does calculations.

I might add that the coprocessor is a pic 16f84 running at 20Mhz, WOO! This gives 5mips per sec. The host computer is my trusty 13 year old z80 home brew systems. I will write some nice maths intensive apps soon. Signal processing of audio comes to mind.

The maths routines i lifted of some websites but include integer signed 16bit addition. Subtraction, with 16bit result. 8 bit multiply for speed,16 bit multiply with 32 bit result, 16bit divide with 16bit result. bcd to binary and binary to bcd conversion.

I had to deal with a few bugs, particularly with the routines that handle multiply and divide, but ive fixed that now, there where also a few instances where i hadnt masked of unused bits in the command selection routine that happens after calling the serial port recieve routine which made some random things happen. Lol. But all is ok.Ive added extra commands to enable intenal moving of numbers about for running multiple calculations while cutting the amount of data reception and transmission down. Also optimised the code in places for faster throughput. I might add theres only 1Kb of program memory and ive still got about 100 bytes left so i could add another function if i wanted.