stall.a51

fx2 gpifFIFOREAD方式实现高速数据传输数据固件

$NOMOD51
$nolist
$include (..\..\target\inc\fx2regs.inc)
$list

NAME      stall


bmEPSTALL equ 01h


; void modify_endpoint_stall(BYTE epid, BYTE stall)
; void modify_endpoint_stall(R7, R5)
;
; Description:
;     routine to set or clear the stall bit for the selected endpoint
; Arguments:
;     epid - the USB endpoint number (direction + ep number)
;     stall - if 1 set the stall bit, else clear the stall bit
;
?PR?modify_endpoint_stall?MODULE	segment code

PUBLIC		_modify_endpoint_stall

rseg	?PR?modify_endpoint_stall?MODULE

_modify_endpoint_stall:

   mov   a,R7     ; endpoint id

   mov   R6,#0 ; register index (R6)
   xrl   a,#0x01
   jz    swdone

   inc   R6
   xrl   a,#0x80      ;0x80 = 0x81 ^ 0x01.
   jz    swdone

   mov   a,R7
   anl   a,#0x0F
   rr    a
   inc   a
   mov   R6,a

swdone:

   mov   dptr,#EP1OUTCS
   mov   a,R6
   add   a,dpl
   mov   dpl,a

   movx  a,@dptr

   cjne  r5,#1,clearstall
   orl   a,#bmEPSTALL
   sjmp  done
   
clearstall:

   anl   a,(0xFF-bmEPSTALL)
   
done:

   movx  @dptr,a
   
   ret

   END