i2cm_write stuff; fixes to needwrite etc.

diff --git a/detpic/mascan.asm b/detpic/mascan.asm
index 92ce97304d016025c6c500875ae352d1b2a14af6..1a2f804fe44af633e069901b0d495cdf95b34a60 100644 (file)
--- a/detpic/mascan.asm
+++ b/detpic/mascan.asm
@@ -15,6 +15,10 @@ cbyte        res     1
        ;       M0B1 0000       we're expecting more detection byte 1
        ;       M010 0000       we're expecting more detection byte 2
        ;       1000 0000       we're expecting an extra byte
+       ;       ???? ???1       reading halted due to lack of buffer space:
+cbyte_halted equ 0 ; also set briefly while we decide what to do next
+
+wslave res     1       ; slave we need to write to
 
 ;======================================================================
 ; HANDLING OF I2C EVENTS
@@ -37,12 +41,6 @@ i2cmu_write_next_byte
        bs_f    STATUS, Z
        return
 
-       bra_nz  write_another_slave
-
-       
-
-       return
-
 ;----------------------------------------
 i2cm_intrl
 ; handles i2c interrupt using i2cm_interrupt[_definite],
@@ -200,17 +198,20 @@ i2c_arrange_next_byte
 ; DECIDING WHICH SLAVE TO ADDRESS
 ;...
 i2c_arrange_something
-i2cmu_done
 ; figure out what to do next - which pic to address, etc.
-       mov_fw  needwrite_slave
-       bra_nz  arrange_write
+       bs_f    cbyte, cbyte_halted
+
+       tst_f_ifnz wslave       ; anyone asked to write ?
+       bra     arrange_write
+nextslave_nowrite
+       ; no writing needed, we consider reading:
+       neg_fw  outmsg_begin
+       add_wfw outmsg_end
+       and_lw  outbuf_size - 1
+       cmp_fw_ifle outmsg_targetlen
+       return ; target len < actual len, do not add anything
+       ; ok, there's space, go ahead:
 
-       ; add calls to needwrite_<foo> here:
-       call    needwrite_polarity
-       call    needwrite_points
-       ; end of list of calls to needwrite_<foo>
-
-       ; no writing needed, we have to read:
        mov_lfsr slavetable, 1  ; FSR1H -> slavetable
        mov_ff  cslot, FSR1L    ; FSR1 -> current ste_flags
        mov_lw  ste_size        ; W = ste_size
@@ -223,16 +224,69 @@ nextslave_reloop_resume
        mov_ff  FSR1L, cslot    ; cslot -> new ste_flags
        bt_f_if1 POSTDEC1, stf_sentinel ; FSR1 -> ste_slave
        bra     nextslave_reloop
+       ; no wrap around:
 
        mov_fw  INDF1           ; W = new slave number
+       bc_f    cbyte, cbyte_halted
        goto    i2cm_read_start
 
 nextslave_reloop
        mov_lfsr slavetable + ste_size + ste_flags
        bra     nextslave_reloop_resume
 
-fixme do not i2cm_read_start if no room in buffer
-fixme check that we don't accidentally skip reading a slave
+;----------------------------------------
+i2cmu_done
+       ; So we've done one write.
+       bs_f    cbyte, cbyte_halted
+
+       tst_f_ifnz wslave       ; anyone asked in the meantime ?
+       bra     arrange_write
+
+       ; Anyone else to write to ?
+       ; add calls to needwrite_<foo> here:
+       call    needwrite_polarity
+       call    needwrite_points
+       ; end of list of calls to needwrite_<foo>
+
+       ; no, if we're here, no-one wants to write
+       bra     nextslave_nowrite
+
+;----------------------------------------
+i2c_needwrite
+; Informs mascan that we need to write to some slave.
+; Some time after this, mascan will call getwritebyte_<everything>
+; and this must yield at least one byte to write.
+;  W           slave that we must write to
+       mov_wf  wslave
+       bt_f_if0 cbyte, cbyte_halted
+       return ; we're currently doing something
+;...   
+;----------
+arrange_write
+;  wslave      slave to write to
+       bc_f    cbyte, cbyte_halted
+       mov_fw  wslave
+       mov_wf  cwslave
+       clr_f   wslave
+       goto    i2cm_write_start
+
+;----------------------------------------
+i2c_consider_restartread
+       bt_f_if0 cbyte, cbyte_halted
+       return
+       bra     nextslave_nowrite
+
+;======================================================================
+; INITIALISATION
+
+mascan_init
+       add_lw  -maxpic/2       ; at 9600, about 1ms per char;
+                               ; we reckon on about 2 pics per ms.  So if
+                               ; we have at least maxpic/2 then we won't
+                               ; run out before we have scanned them all
+                       coincidentally is about 1 pic   cmp_fw_ifle 
+                       mov_fw  outmsg_end
+                       sub_wfw 
 
 ;======================================================================
 ; PROCESSING OF INCOMING BYTES - EXTRA (NON-DETECTION)

diff --git a/detpic/reverse.asm b/detpic/reverse.asm
index 1e57c37cf1018d757e3012bd4433418eba761e9d..236e01edc0b01aee5628f213edb690c86ee9102a 100644 (file)
--- a/detpic/reverse.asm
+++ b/detpic/reverse.asm
@@ -199,9 +199,8 @@ polarity_needwrite_loop
 
        mov_fw  FSR1L
        add_lw  -polarity_cmds
-       mov_wf  needwrite_slave
        pop
-       return
+       goto    i2c_needwrite
 
 near_getwritebyteyes code
 ;----------------------------------------------------------------------

diff --git a/detpic/serout.asm b/detpic/serout.asm
index 7dbd6d2336b95060d5e219ec7725412b633b24dc..33d9b2b6bd5ee21d2b7ee4ea60fcd6e7e7669b0d 100644 (file)
--- a/detpic/serout.asm
+++ b/detpic/serout.asm
@@ -58,7 +58,8 @@ serialtx_intrl
 tx_justsent_noacknmra
        inc_f   outmsg_begin
        bc_f    outmsg_begin, outbuf_szln2
-       goto    led_green
+       call    led_green ; we're transmitting
+       goto    i2c_consider_restartread
 
 tx_bufempty
        ; maybe we send an NMRADONE
@@ -66,7 +67,7 @@ tx_bufempty
        bra_nz  tx_acknmra_send
        ; nothing at all to do:
        bc_f    PIR1, TXIE
-       goto    led_black
+       goto    led_black ; we're not transmitting
 
 tx_acknmra_insert
        sub_wff acknmra ; we're acking these now
@@ -95,7 +96,7 @@ portb_read
 tx_fcdisable
        bc_f    PIR1, TXIE
        bs_f    INTCON, RBIE
-       goto    led_red
+       goto    led_red ; flow control forces us not to transmit
 
 ;----------------------------------------------------------------------
 serialtxfc_init

diff --git a/detpic/variables.asm b/detpic/variables.asm
index 90db76059081fa18d029a0cd8bbfc669bdd83026..b1edb4f291fb46bb0300d96ad27f5d08809f3fd0 100644 (file)
--- a/detpic/variables.asm
+++ b/detpic/variables.asm
@@ -27,11 +27,7 @@ isr_high_save_fsr0   res     2 ; for isrh_fsr0_{save,restore}
 
 xdebug                 res     8
 
-; for writing to slaves:
 cwslave                        res     1 ; slave we're currently actually writing to
-needwrite_slave                res     1 ; 0 means we don't need to write to any slave
-                                 ; non-0 means at least this slave
-                                 ; and perhaps others
 
 qqtrislat_start equ 0x50
 qqtrislat_section udata qqtrislat_start