The AVR micros from Atmel are becoming quite popular, due in part to their ease of programming and a good Basic compiler along with gcc for C development. You can program many AVRs with our XCP1 JTAG kit (which is actually meant to program Xilinx CPLDs).
If you use gcc, you will want to check out our PAKs and GCC page (which uses an ATMega 16 as an example). If you prefer assembly language, keep reading!
The PAKs will work fine with the AVR. I've written an assembly language library that lets you use a PAK-I or PAK-II floating point math coprocessor with an AVR. The library is wrapped in BASCOM subroutines so that you can use it from Basic or pull the routines out for use with assembly language. Of course, if you are using Basic you might just as well use SHIFTIN and SHIFTOUT. You'll have to tune the delays to match your processor speed, but otherwise you shouldn't have to do much to get it to work. It would be easy to adapt the library to work with PAK-III, IV, VII, VIII, or IX parts.
Here is a simple program that uses the library:
' Example for PAK1.INC. See PAKDEF.INC for instructions ' and more info $crystal = 1000000 Config Pinb.0 = Output ' indicator led Dim X0 As Byte ' general-purpose Dim Iresult As Integer ' General integer ' Get PAK library definitions $include c:\pakdef.inc Wait 5 ' reset delay X0 = &HFF Call Pakreset ' always reset first Top: Pakdir &HFF ' all outputs Pakwio X0 ' write to outputs If X0 = &HFF Then X0 = 0 Else X0 = &HFF ' toggle for next time Reset Portb.0 ' Turn on LED ' Compute 1/2 * 10 using integers ' Could also use FConvert to preconvert these to floats and ' and load them directly Pakloadint 2 Pakswap Pakloadint 1 Pakdiv Pakswap Pakloadint 10 Pakmult Iresult = Pakreadint() ' Answer better be 5! If Iresult = 5 Then Set Portb.0 Wait 10 ' do it all again Goto Top ' Get PAK library code $include c:\pak1.inc End
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