\ 2011-05-29  EW  ewlib/rfm12.fs
\ words: +rfm12 rfm12.init
\        >wc wc? w? >w

\ wait for wireless data tx ready
: w? ( -- )
  _rfm12 low
  begin _miso pin_high? until
;
\ write 1 cell to wireless control
: (>wc) ( x -- x' )
  _rfm12 low ><spi _rfm12 high ;
\ write wireless control, drop reply
: >wc ( x -- )    (>wc) drop ;
\ read wireless status
: wc? ( -- x )  0 (>wc)      ;
: w.status wc? 4 hex u0.r ;

\ write wireless data
: >w ( c -- )
  $00ff and $b800 +
  w? (>wc) drop
;
\ read one byte
: <w ( -- c )
  $b000
  w? (>wc)
;

: +rfm12
  _rfm12 low _rfm12 pin_output
;
: rfm12.init
  \ read status register
\  wc? drop
  \ init sequence
  $80d7 >wc
  $82d9 >wc \
\ Band Mitte: 433.920 MHz
\ $a67c >wc \ 434.150 MHz;  
  $a6b8 >wc \ 434.300 MHz
\ $a530 >wc \ 433.620 MHz
  $c647 >wc \ 4800 baud
  $94a0 >wc \ bandwith: 134 kHz
\ $9480 >wc \           200 kHz
  $c2ac >wc
  $ca81 >wc
  $c483 >wc \ AFC
\ $c400 >wc \ AFC test without
  $9854 >wc \ (5+1)*15 = 90 kHz Hub, -12dB
\ $9857 >wc \ (5+1)*15 = 90 kHz Hub, -21dB
\ $9894 >wc \ (9+1)*15 = 150 kHz
  $e000 >wc
  $c800 >wc
  $c000 >wc
;

\ Sende/Empfangsfrequenz
\ f = 10 * C1 * ( C2 + F/4000 ) [MHz]
\ 434 MHz: C1 = 1  C2 = 43
\ F:  96 <= F <= 3903
\ 
\ f = 10 * 1 * ( 43 +  F[0..11]/4000 )
\     10     * ( 43 +  $06b8/4000 )
\     10     * ( 43 +   1720/4000 )
\   = 434.300 MHz
\ f:  430.24 <= f <= 439.75 [MHz]
\ hub: Df = (M[0..3] + 1) * 15 kHz