Sun Oct 26 11:52:40 CET 2008


Got distracted a bit by ideas of using CANbus or RS485 as a way to
connect measuring equipment to a PC.  Currently I'm thinking of trying
to make an ISA card with DMA.  As long as the card is not bus master,
this shouldn't be too hard.  However, it does need buffering on the
PIC side, so is limited to slow data rates (not possible to run a
single loop).

So, the easiest route is the FTDI on 460800 baud with plain 8 bit port
readout.  For PIC18 @ 40 MHz that's a divisor of 21.7   And on 48 Mhz
it's 26.

The reason i'm dragging my feet here is that i don't have a decent
workflow setup.  This application (getting serial comm to work) can be
used as a comb for workflow documentation.

  1. Create a standalone application:  .f -> .hex
     This involves: processor selection + oscillator configuration.
     Maybe this is a good time to also use standard config bits
     defines from the asm files.

  2. Time base + delay loops.  Use this to create a bit-banged serial
     send, and later receive.

  3. hardware UART config.

The deal is this: get the monitor config working using just busy loops
and general purpose IO.  This leads to simple examples.  It removes
dependency on hardware uart (i.e. when uart is used by app, or chip
doesnt have one).  It should be enough to get the PK2 serial port
working too.