* miscellaneous definitions
HResMaxX equ   639        high resolution X limit
HResMaxY equ   191        high resolution Y limit
MousData equ   $0008      arbitrary choice for mouse data area ($0008-$000F)
PcktSize equ   5          number of bytes in mouse data packet
SyncData equ   %10000000  initial mouse data byte pattern
SyncMask equ   %11111000  mask for initial mouse data byte pattern

* 6551 register definitions
         org   0
DataReg  rmb   1          receive/transmit data
StatReg  rmb   1          IRQ/DSR/DCD/error status (read only)
PRstReg  equ   StatReg    programmed reset (write only)
CmdReg   rmb   1          command (parity/echo/Tx IRQ/Rx IRQ/DTR)
CtrlReg  rmb   1          control (stop bits/word length/Rx clock/baud rate)

* Status bit definitions
Stat.IRQ equ   %10000000  IRQ occurred
Stat.DSR equ   %01000000  current DSR input level (0=enabled, 1=disabled)
Stat.DCD equ   %00100000  current DCD input level (0=enabled, 1=disabled)
Stat.TxE equ   %00010000  Tx register empty
Stat.RxF equ   %00001000  Rx register full
Stat.Ovn equ   %00000100  overrun error
Stat.Frm equ   %00000010  framing error
Stat.Par equ   %00000001  parity error

Stat.Err equ   Stat.Ovn!Stat.Frm!Stat.Par status error bits
Stat.Flp equ   $00        all status bits active when set
Stat.Msk equ   Stat.RxF!Stat.Ovn!Stat.Frm!Stat.Par active IRQ bits

* Command bit definitions
Cmd.Par  equ   %11100000  see parity table below
Cmd.Echo equ   %00010000  Rx echo (0=disabled, 1=enabled)
Cmd.TxIC equ   %00001100  see Tx IRQ control table below
Cmd.RxIE equ   %00000010  Rx IRQ enable (0=enabled, 1=disabled)
Cmd.DTR  equ   %00000001  DTR output (0=disabled, 1=enabled)

* parity table
Par.None equ   %00000000
Par.Odd  equ   %00100000
Par.Even equ   %01100000
Par.Mark equ   %10100000
Par.Spac equ   %11100000

* Tx IRQ control table
TIC.Off  equ   %00000000  RTS disabled, Tx IRQ disabled
TIC.On   equ   %00000100  RTS enabled, Tx IRQ enabled
TIC.RTS  equ   %00001000  RTS enabled, Tx IRQ disabled
TIC.Brk  equ   %00001100  RTS enabled, Tx line break

* Control bit definitions
Ctl.Stop equ   %10000000  stop bits (clear=1, set=2)
Ctl.DBit equ   %01100000  see data bit table below
Ctl.RClk equ   %00010000  Rx clock source (0=external, 1=internal)
Ctl.Baud equ   %00001111  see baud rate table below

* data bit table
DB.5     equ   %01100000  five data bits per character
DB.6     equ   %01000000  six data bits per character
DB.7     equ   %00100000  seven data bits per character
DB.8     equ   %00000000  eight data bits per character

* baud rate table
         org   0
BR.ExClk rmb   1          16x external clock
BR.00050 rmb   1          50 baud
BR.00075 rmb   1          75 baud
BR.00110 rmb   1          109.92 baud
BR.00135 rmb   1          134.58 baud
BR.00150 rmb   1          150 baud
BR.00300 rmb   1          300 baud
BR.00600 rmb   1          600 baud
BR.01200 rmb   1          1200 baud
BR.01800 rmb   1          1800 baud
BR.02400 rmb   1          2400 baud
BR.03600 rmb   1          3600 baud
BR.04800 rmb   1          4800 baud
BR.07200 rmb   1          7200 baud
BR.09600 rmb   1          9600 baud
BR.19200 rmb   1          19200 baud

* Btn.Cntr bit definitions
BC.Butn1 equ   %00100000  button #1 (left, 1 = pressed)
BC.Butn2 equ   %00010000  button #2 (middle, 1 = pressed)
BC.Butn3 equ   %00001000  button #3 (right, 1 = pressed)
BC.RxCnt equ   %00000111  Rx data counter

BC.Butns equ   BC.Butn1!BC.Butn2!BC.Butn3 mask for all buttons


* mouse static data area definitions
         org   0
Btn.Cntr rmb   1          mouse button status and Rx data counter
Buffer   rmb   3          Rx buffer for 1st 3 bytes of XY mouse data (must start at 1,u)
CrntXPos rmb   2          mouse X position (0 to HResMaxX)
CrntYPos rmb   2          mouse Y position (0 to HResMaxY*2)