--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/level1/modules/dw3.asm	Sat Mar 07 20:04:42 2009 +0000
@@ -0,0 +1,94 @@
+********************************************************************
+* DW3 - DriveWire 3 Low Level Subroutine Module
+*
+* $Id$
+*
+* Edt/Rev  YYYY/MM/DD  Modified by
+* Comment
+* ------------------------------------------------------------------
+*   1      2008/01/26  Boisy G. Pitre
+* Started as a segregated subroutine module.
+
+         nam   DW3
+         ttl   DriveWire 3 Low Level Subroutine Module
+
+         ifp1
+         use   defsfile
+         use   dwdefs.d
+         endc
+
+tylg     set   Sbrtn+Objct   
+atrv     set   ReEnt+rev
+rev      set   $01
+
+         mod   eom,name,tylg,atrv,start,0
+
+name     fcs   /dw3/
+
+* DriveWire subroutine entry table
+start    lbra   Init
+         bra    Read
+	 nop
+         lbra   Write
+
+* Term
+*
+* Entry:
+*    U  = address of device memory area
+*
+* Exit:
+*    CC = carry set on error
+*    B  = error code
+*
+Term
+         clrb				clear Carry
+         rts
+
+* Init
+*
+* Entry:
+*    Y  = address of device descriptor
+*    U  = address of device memory area
+*
+* Exit:
+*    CC = carry set on error
+*    B  = error code
+*
+* Initialize the serial device
+Init  
+         clrb				clear Carry
+         pshs  cc,x			then push CC on stack
+         orcc  #IntMasks
+         ldx   #PIA1Base		$FF20
+         clr   1,x			clear CD
+         lda   #%11111110
+         sta   ,x
+         lda   #%00110100
+         sta   1,x
+         lda   ,x
+         puls  cc,x,pc
+
+* Read
+*
+*  ON ENTRY:
+*    X = ADDRESS OF THE RECEIVE BUFFER
+*    A = TIMEOUT VALUE (182 = APPROX ONE SECOND @ 0.89 MHz)
+*
+*  ON EXIT:
+*    Y = DATA CHECKSUM
+*    D = ACTUAL NUMBER OF BYTES RECEIVED
+*    X AND U ARE PRESERVED
+*    CC.CARRY IS SET IF A FRAMING ERROR WAS DETECTED
+*
+Read  
+       use  dwread.asm
+         
+* Write
+*
+* Entry:
+Write    
+         use   dwwrite.asm
+
+         emod
+eom      equ   *
+         end