switch nmra timer ISR to use FSR2 and reserve FSR2 for it

diff --git a/detpic/common.inc b/detpic/common.inc
index d8429605287514c1d2c1aad7cc40e4bafdae1921..663741b596d02c4e65717825a3a102b48069bc95 100644 (file)
--- a/detpic/common.inc
+++ b/detpic/common.inc
@@ -33,7 +33,7 @@ clock equ -1
 ;   PCLATH             Low ISR                 Not used
 ;   t_dolocal          Low ISR                 High ISR
 ;   FSR1               Low ISR                 High ISR (detect[1])
-;   FSR2               Low ISR                 High ISR (detect[1])
+;   FSR2               High ISR (nmra)         High ISR (detect[1])
 ;
 ; Trashed      May be trashed by any routine anywhere.  Saved
 ;              during every ISR entry/exit.
@@ -68,7 +68,9 @@ clock equ -1
 ; saves that register for the benefit of its callers.
 ;
 ;  [1] FSR1 and FSR2 on slave pics are reserved exclusively for the
-;      I2C response and detection code (detect.asm), after det_slave_init.
+;      I2C response and detection code (detect.asm), after
+;      detect_slave_init.  Likewise FSR2 is reserved exclusively
+;      for the NMRA output ISR after nmra_init.
 ;
 ; General-purpose hardware allocation:
 ;

diff --git a/detpic/nmra-stream.asm b/detpic/nmra-stream.asm
index 6ff993ade54915d24420c5cb7cdf08cd3143e39c..695b18d7061eb81440e0b41b7e65704f5a46f3a3 100644 (file)
--- a/detpic/nmra-stream.asm
+++ b/detpic/nmra-stream.asm
@@ -27,7 +27,7 @@ nextaction    equ     6       ; bit 6: change polarity on next interrupt y/n
  ; nmractrl is a bitmask, and only the bits above are used
 
 fromserial     res     1       ; from-serial buffer location (in buffer bank)
-totrack                res     1       ; to-track buffer location (in buffer bank)
+totrack                equ     FSR2L   ; to-track buffer location (in buffer bank)
 totrackbit     res     1       ; bit location of pointer within byte
  ;
  ; buffers are each 16 bytes (this is hardwired)
@@ -142,6 +142,7 @@ nmra_init
 ; initialise buffers (for bank 5, for nmra from-serial/to-track buffers)
 
        mov_lw  bufferpage
+       mov_wf  FSR2H
 
        clr_fa  nmractrl        ; for bits relevant to control of nmra stream
        clr_fa  fromserial      ; for loc'n of write-from-usart ptr in buffers
@@ -351,13 +352,8 @@ read_from_buffer
 ; set na=cb=bit value, advance bit (i.e. rotate transmitbit right), 
 ; check if bit7, if so, advance byte, return
 
- fixme save and restore FSR1
- fixme check other to-be-saved stuff ??
        debug   'p'
-       mov_ff  totrack,FSR1L           ; set low byte of IND1 pointer
-       mov_lw  bufferpage
-       mov_wfa FSR1H                   ; set high byte of IND1 pointer
-       mov_ff  INDF1,WREG
+       mov_ff  INDF2, WREG
        and_wfwa totrackbit             ; select bit to be transmitted
 
        bra_z   zero_bit_to_track 
@@ -403,17 +399,14 @@ advance_pointer
 
 ; currently on bit 7 of the byte, after having read rest of byte to
 ; track; check whether it is 1 or 0
-       mov_ff  totrack,FSR1L   
-       mov_lw  bufferpage
-       mov_wfa FSR1H           
 
 ; if set, move to next buffer
-       bt_fa_if1 INDF1,7  
+       bt_fa_if1 INDF2,7  
        call    advance_read_buffer
 
 ; if not set, move to next byte of samebuffer (increment totrack)
 ; (will be on bit 7 at this point anyway so no need to change totrackbit)
-       bt_fa_if0 INDF1,7  
+       bt_fa_if0 INDF2,7  
        inc_fa  totrack    
        return