With regards to my earlier posting, I would like to get comments on the
following.

Note that DS00548C has bugs in it - the BCF ALUSTA,5 in each example should
be followed by BSF ALUSTA,4 to set the increment mode properly.

If anybody has a 17C ICE and can give this a test I'd really appreciate it
- I have yet to get the hardware.

Thanks.

Andy




/****************************************************************************
**                                                                         **
**                          External RAM Access Routines                   **
**                                                                         **
****************************************************************************/
//
//      This module provides an interface to permit a device to communicate
//      with external RAM and ROM for buffering messages, etc.
//

#ifndef CLRWDT
#include "pic.h"
#include "string.h"
#endif
#define EXTRAM_C
#include "defs.h"               // definitions of data types, etc.

//
//............................................................................
//
//      ram_write_block
//
//      Copy block of register RAM to external SRAM.  This routine handles the
//      blocking needed to write a large block of data.
//
//      NOTE:  This routines writes 16-bit values, not 8-bit bytes!!!
//
//      INPUTS:
//              on stack -
//                      External address to receive data (address)
//                      Internal RAM address to read from (source[])
//                      Number of words to write (count)
//
//      OUTPUTS:
//              on stack - number of bytes written
//
//      Author:         Andy Kunz
//      Date:           00-00-98
//      Modifications:  none
//
// Based on DS00548C
//
byte ram_write_block (UINT address, UINT source[], byte count)
        {
        byte    i;                              // Index into source[]
        UINT    element;

        TBLPTR = address;
        ALUSTA &= 0b10011111;                   // Set FS1:FS0 to auto-inc FSR0
        ALUSTA |= 0b00100000;

        FSR0 = address;

        i = 0;
        do
                {
                asm ("tlwt 1,0");
                asm ("tablwt 0,1,0");           // Write and increment
                }
        while (--count);
        }
//
//............................................................................
//
//      ram_read_block
//
//      Read block of data from external RAM or ROM into internal RAM
//
//      NOTE:  This routines reads 16-bit values, not 8-bit bytes!!!
//
//      INPUTS:
//              on stack -
//                      pointer to destination (dest[])
//                      address of external RAM/ROM  (address)
//                      number of words to fetch (count)
//
//      OUTPUTS:
//              data at dest[] updated in place
//
//
//      Author:         Andy Kunz
//      Date:           00-00-98
//      Modifications:  none
//
// Based on DS00548C
//
void ram_read_block (UINT dest[], UINT address, byte count)
        {
        byte    i;                              // Index into source[]

        TBLPTR = address;
        ALUSTA &= 0b10011111;                   // Set FS1:FS0 to auto-inc FSR0
        ALUSTA |= 0b00100000;

        asm (" tablrd 1,1,_i");
        i = 0;

        FSR0 = dest;                            // Point to destination

        do
                {
                asm (" tlrd   1,0");            // Read a byte & store
                asm (" tablrd 0,1,0");          // Read next byte & store
                }
        while (--count);
        }

==================================================================
Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
==================================================================