collapseos/blk/691
Virgil Dupras 1a6a549857 Make the SPI Relay protocol support multiple devices
Working on programming AVR chips exposes a glaring omission in my
first design of the SPI Relay: not allowing multiple devices make
this task hard. I constantly have to unplug my SD card before, plug
the AVR chip holder, then play a bit, then unplug the AVR holder,
then replug the SD card...

My prototype for a SPI relay design is built, but I haven't tested
it yet. I need to adapt the code first, which is what I do here.

When the prototype is tested, I'll update the SDC recipe with a new
schema.
2020-09-17 09:48:55 -04:00

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( page size in words, 64 is default on atmega328P )
CREATE aspfpgsz 64 ,
VARIABLE aspprevx
: _x ( a -- b ) DUP aspprevx ! (spix) ;
: _xc ( a -- b ) DUP (spix) ( a b )
DUP aspprevx @ = NOT IF ABORT" AVR err" THEN ( a b )
SWAP aspprevx ! ( b ) ;
: _cmd ( b4 b3 b2 b1 -- r4 ) _xc DROP _x DROP _xc DROP _x ;
: asprdy ( -- ) BEGIN 0 0 0 0xf0 _cmd 1 AND NOT UNTIL ;
: asp$ ( spidevid -- )
( RESET pulse ) DUP (spie) 0 (spie) (spie)
( wait >20ms ) 5000 0 DO LOOP
( enable prog ) 0xac (spix) DROP
0x53 _x DROP 0 _xc DROP 0 _x DROP ;
: asperase 0 0 0x80 0xac _cmd asprdy ;