The WiPo mouse 99

This mouse was produded around 1986 by:

Softpoint Electronic, GmbH
Balanstr. 285 8000 Munchen 90
Germany

Hardware description

Software issues
CRU map
Mouse driver
Text mode


Hardware

The hardware consists in a small 6-chip adapter board that is plugged in the side port of the console, in between the console and the PE-Box cable connector. This design serves two functions: first the board can draw its power supply from the side port. Second, it can access the LOAD* line to issue non-maskable interrupts when the mouse is moved. An easily accessible switch allows the user to open this connection and to prevent interrupt from being sent when the mouse driver is not installed.

In addition, the board has a 9-wire connection cable to the joystick port. This enables the software to read the status of the two mouse buttons, and of the two motion detectors (left/right and up/down). The circuitery on board provides an extra signal that the software can use to determine whether the latest detected motion (that triggered the interrupt) was vertical or horizontal. These signals can be accessed by reading keyboard column 7, i.e. joystick 2.

Reading keyboard column 6 (joystick 1) temporarily prevents the emission of LOAD* interrupts. This avoids the re-entrancy problems due to two interrupts issued too close from each other (see my page on interrupts for more details). It also resets the vertical/horizontal flip-flop.

The mouse itself is a "no name" device made in Taiwan. It has a long cable with a 9-hole plug at the end, just like the joystick port. A corresponding male socket is provided on the adapter board.

      74LS121           74LS74    M3     74LS123
      +------+         +------+   v      +------+    2K
J7>---|A1*  R|-+5V +5V-|D     |   |  Gnd-|A*  CR|-+--WWW--+5V
  +5V-|A2*   |     +5V-|Pr*   |   |      |      | = 333
  +5V-|B    C|-,       |   Clk|---+------|B   C |-'
      |      | = 0.1uF |      |          |      | 
      |    CR|-'       |      |      +5V-|Clr*  |
      |    Q*|----+----|Clr* Q|--,       |    Q*|--,
      +------+    |    +------+  |       +------+  |      74LS04
                  |              |   Gnd-|A*  Q*|--==|)---|>o---, 74LS08  Switch
                  |              |   +5V-|B     |  74LS08      ,==|)--|>o--/ o---> LOAD* 
                  |              |       |    C |-,            |     74LS04
                  |              | M1>---|Clr*  | = 333        |
                  |              |       |    CR|-+--WWW--+5V  |   
                  |              |       +------+    2K        |
                  '--------------|-----------------------------'     
             74LS367             |
           +--------+            |
 J2>----+--|1OE* 2A2|------------'            
        '--|2OE* 2Y2|----->J8          +5V----M7
           |        |                  Gnd----M8              ___________
 M4>-------|1A1  2A1|-----<M2            nc --M5             ( 1 2 3 4 5 )
 J9<-------|1Y1  2Y1|----->J3                                 \ 6 7 8 9 /
           |        |  
 M6>-------|1A2  1A4|-----<M9            nc --J1            M1-M9: Mouse plug
 J4<-------|1Y2  1Y4|----->J3            nc --J6            J1-J9: Joystick port
           +--------+

A rising edge on mouse connections M3 (vertical motion) and M1 (horizontal motion) triggers a short pulse in their respective half of the 74LS123 one-shot. The two Q* outputs are combined via an AND gate so that, if at least one pulse is occuring, the LOAD* line will be low. The second AND gate is used to mask out this signal: when joystick 1 is accessed, it triggers a longer pulse on the 74LS121 one-shot. The resulting low signal on the Q* output prevents the LOAD* line from going low, no matter what happened to the mouse.

Accessing joystick 2 enables the 74LS373 tri-state buffer and allows for reading the four mouse signals through the joystick return lines. The fifth line is connected to the Q output of a 74LS74 flip-flop: it is used to determine whether a vertical motion was detected or not. A rising edge on M3 brings the Q output high, it can only be reset by accessing joystick 1.


Software

The mouse came with a companion disk containing completely useless demo software and very meager explanations on how to write a mouse driver. I had to experiment quite a bit in order to figure out how to access the mouse!

CRU map

R12 address Bit Meaning
>0006 3 Left button. 0: down 1: up
>0008 4 Right button. 0: down 1: up
>000A 5 Vertical motion. 0: down 1:up
>000C 6 Motion detector. 0: horizontal 1: vertical
>000E 7 Horizontal motion. 0: right 1: left
>0024
>0026
>0028		 18
19
20		 1 1 1: read mouse values in bits 3-7
0 1 1: temporarily disable LOAD* interrupts
and reset bit 6.


Mouse driver

The software must hook the non-maskable interrupt vector at >FFFC-FFFF to trap any interrupt generated by the mouse. The interrupt service routine can then read CRU bits 4-6 to determine what kind of motion caused the interrupt and update the vertical and horizontal position buffers.

The value of these counters can then be used by the program to display a mouse cursor on screen. A good way to do this is to hook the VDP interrupts that occur 60 times per second (50 in Europe) and update the position of a sprite according to the moves of the mouse.

*======================================================================
* Demo driver for the WiPo mouse 99
* ---------------------------------
* It moves a sprite on screen according to the moves of the mouse
* (without checking for screen boundaries).
* The left mouse button changes the sprite pattern (crosshair/arrow).
* The right button changes the sprite color (black/white).
*======================================================================
       DEF  START
*
START  LI   R0,>0400       initialize sprite patterns
       LI   R1,PATS
       LI   R2,16          2 chars: crosshair and arrow
       BL   @VMBW
       LI   R0,>0300       initialize sprite 0 attributes
       LI   R1,SPRITE
       LI   R2,5
       BL   @VMBW
 
       LI   R0,INTER       hook the VDP interrupt routine
       MOV  R0,@>83C4
 
       CLR  @WREGS+18      reset motion counters (R9 and R10 in WREGS)
       CLR  @WREGS+20
 
       MOV  @YSWR,@>FFFC   hook the LOAD* interrupt vectors
       MOV  @YSPG,@>FFFE
 
EVER   LIMI 2              enable VDP interrupts
       LIMI 0              disable them
       JMP  EVER           wait forever (Fctn= is active)

*-------------------------------------------
* Unmaskable LOAD* interrupt service routine
*-------------------------------------------
CHECK  MOV  @NOWR,@>FFFC   change WS to allow 1 re-entrancy
       LIMI 0              disable VDP interrupts
       LWPI WREGS          our workspace
       MOV  @NOPG,@>FFFE   prevents re-entrancy (this points to a RTWP)
 
       CLR  R12            CRU address of the TMS9901
       SBO  18             keyboard column 7 (joystick 2) to read mouse param
       SBO  19
       SBO  20
 
       TB   6              vertical or horizontal interrupt?
       JNE  SK1            horizontal
       INC  R9             vertical: increment counter
       TB   5              up or down?
       JEQ  SK2            up: we are done
       DECT R9             down: we should have decremented the counter
       JMP  SK2
 
SK1    INC  R10            horizontal motion: increment the counter
       TB   7              left or right?
       JEQ  SK2            right: we are done
       DECT R10            left: we should have decremented the counter
 
SK2    SBZ  18             reset bit 6, disable LOAD* interrupts for a while
       MOV  @YSWR,@>FFFC   restore the LOAD* vectors
       MOV  @YSPG,@>FFFE   no interrupt should occur here!
RET    RTWP
 
*-------------------------------------------
* Display routine, hooked to the VDP interrupt service routine
*-------------------------------------------
INTER  LIMI 0              disable interrupts (just in case)
       LWPI WREGS          our workspace
       LI   R0,>0300       read sprite 0 attributes
       LI   R1,BUF
       LI   R2,4
       BL   @VMBR1
 
       LI   R1,BUF         update the position
       SLA  R9,8           to slow the sprite: SLA R9,7 To speed it up: SLA R9,9 
       AB   R9,*R1+        add the vertical motion
       SLA  R10,8
       AB   R10,*R1+       add the horizontal motion
 
       CLR  R12            CRU address of the TMS9901
       SBO  18             keyboard column 7: access mouse params
       SBO  19
       SBO  20
 
       LI   R0,>8000       sprite pattern # 128 (crosshair)
       TB   3              test left button
       JEQ  SK3            up
       AI   R0,>0100       down: change for pattern # 129 (arrow)
SK3    MOVB R0,*R1+        write it back
 
       LI   R0,>0100       color = black
       TB   4              test right button
       JEQ  SK4            up
       LI   R0,>0F00       down: change color to white
SK4    MOVB R0,*1+         write it back
 
       SBZ  18             reset bit 6, temporarily disable LOAD*
       LI   R0,>0300       write back sprite parameters
       LI   R1,BUF
       LI   R2,4
       BL   @VMBW1
 
       CLR  R9             reset counters
       CLR  R10
       LWPI >83E0          back to interrupt service routine workspace
       B    *R11           return to it
 
*-------------------------------------------
* Subroutines used by the above
*-------------------------------------------
VMBR1  SWPB R0             read several bytes from the VDP
       MOVB R0,@>8C02      -------------------------------
       SWPB R0             address in R0
       MOVB R0,@>8C02
LP3    MOVB @>8800,*R1+    data pointer in R1
       DEC  R2             number of bytes in R2
       JH   LP3
       B    *R11
*
VMBW1  ORI  R0,>4000       write several bytes to the VDP
       SWPB R0             ------------------------------
       MOVB R0,@>8C02      address in R0
       SWPB R0
       MOVB R0,@>8C02
LP2    MOVB *R1+,@>8C00    pointer in R1
       DEC  R2             number of bytes in R2
       JH   LP2
       B    *R11
 
*-------------------------------------------
* Data
*-------------------------------------------
WREGS  BSS  18                our main workspace
WREG1  DATA 0,0               temporary workspace for re-entrancy
       BSS  28
BUF    BSS  4                 buffer for sprite data
 
YSWR   DATA WREGS             LOAD* interrupt vectors
YSPG   DATA CHECK
NOWR   DATA WREG1             vectors in use while processing the LOAD* interrupt 
NOPG   DATA RET
SPRITE DATA >6080,>8001,>D000        sprite 0 attributes
PATS   DATA >1010,>10FE,>1010,>1000  crosshair pattern
       DATA >0000,>001E,>1814,>1201  arrow pattern
 
       END


Text mode

Things are more complicated in text mode, as no sprite can be displayed. We must therefore superimpose the mouse cursor to the pattern of the characters it overlaps. This implies to

  • Determine the position of the cursor in terms of characters.
  • Read a 2x2 characters box around this position.
  • Read the patterns of these chars into a buffer.
  • Superimpose the cursor pattern after due shifting up/down and left/right to point to the correct pixel.
  • Assign these patterns to 4 unused characters (e.g. characters 26 to 29).
  • Write these 4 characters into the 2x2 box.
  • When the cursor moves, restore the initial 2x2 characters and repeat the whole process.


    • *=====================================================================
    * Demo on how to displays a cursor pattern in text mode
    * Assume SPROW and SPCOL were set by a routine similar to INTER above
    *=====================================================================

    * These routines set the VDP address for a write/read respectively 
    VWR    ORI  R0,>4000     address in R0
    VRD    SWPB R0
           LI   R14,>8C02           
           MOVB R0,*R14      set address
           SWPB R0
           MOVB R0,*R14
           DECT R14          R14 is >8C00: VDP write port
           LI   R13,>8800    R13 is >8800: VDP read port
           B    *R11

    * This routine reads several bytes from the VDP
    VMBR1  MOV  R11,R8       address in R0
           BL   @VRD
    LP3    MOVB *R13,*R1+    data pointer in R1
           DEC  R2           number of bytes in R2
           JH   LP3
           B    *R8

    * This routine writes several bytes to the VDP
    VMBW1  MOV  R11,R8       address in R0
           BL   @VWR
    LP2    MOVB *R1+,*R14    data pointer in R1
           DEC  R2           number of bytes in R2
           JH   LP2
           B    *R8

    * This routine saves a character definition into a buffer
    * Input: R0msb = char number
    SAVPAT SRL  R0,8
           SLA  R0,3         8 bytes per char
           AI   R0,>0800     address of pattern table
           LI   R2,8
           JMP  VMBR1

    * This routine calculates the screen position of the mouse cursor
    * Inputs: SPROW = pixel row, SPCOL = pixel column
    * Outputs: R0 = screen address (0-3BF), R1 = char column (0-39)
    FPOS   MOV  @SPROW,R1    get pixel row
           SRL  R1,3         chars are 8-pixel high: divide by 8 
           MPY  @H0028,R1    40 columns in text mode
           MOV  @SPCOL,R1    get pixel column
           CLR  R0
           DIV  @H0006,R0    characters are 6-pixel wide
           MOV  R0,R1        R1 = character column
           A    R2,R0          
           MOV  R0,@SCPOS    R0 = screen address
           B    *11          

    * This routine sets a 2x2 character box at the cursor position
    * Inputs: R0 = screen address, R1 = 4-char buffer 
    PUT4CH MOV  R11,R10       save return address
           BL   @VWR         set VDP to write
           MOVB *R1+,*R14    write 2 chars
           MOVB *R1+,*R14
           AI   R0,40        next line
           BL   @VWR         set VDP to write
           MOVB *R1+,*R14    write two chars
           MOVB *R1+,*R14
    SKRD   B    *R2
    * This routine reads a 2x2 character box at the cursor position
    * Inputs: R0 = screen address, R1 = 4-char buffer  
    GET4CH MOV  R11,R10
           LI   1,BUF1       read 4 chars
           BL   @VRD         set VDP to read
           MOVB *13,*1+      read two chars
           MOVB *13,*1+
           AI   0,40         next line
           BL   @VRD         set VDP to read
           MOVB *13,*1+      read 2 chars
           MOVB *13,*1+
           B    *R10
    * This routine displays the cursor pattern on screen
    * Inputs: pixel row in SPROW, pixel column in SPCOL
    PUTCUR MOV  R11,R9       save return point
           BL   @NOCUR       erase existing cursor, if any
           BL   @FPOS        find new cursor position
           BL   @GET4CH      read a 2x2 box into a buffer
           LI   R3,BUF1      copy char patterns into another buffer
           MOVB *R3,R0       get char 1
           LI   R1,BUF2      pattern buffer
           BL   @SAVPAT      save char pattern
           MOVB @2(R3),R0    ditto for char 3 (watch the order!)
           BL   @SAVPAT
           MOVB @1(R3),R0    ditto for char 2
           BL   @SAVPAT
           MOVB @3(R3),R0    ditto for char 4
           BL   @SAVPAT

           MOV  @SPCOL,R1     Now add cursor pattern. Get pixel column
           CLR  R0
           DIV  @H0006,R0     chars are 6-pixels wide
           MOV  R1,R0         pixel column inside character
           MOV  @SPROW,R1     get pixel row
           ANDI R1,>0007      pixel line in character
           AI   R1,BUF2+16    pattern for char 2, at appropriate pixel line
           LI   R2,PATRN      cursor pattern
           LI   R3,8          cursor is 8-pixel high
    LHH0   CLR  R5
           MOVB *R2+,R5       get 1 line from the cursor pattern 
           SRC  R5,0          shift it to begin at appropriate pixel column 
           SOCB R5,@-16(R1)   superimpose it on char 1 (or 3)
           SLA  R5,6          the remainder will be on char 2 (or 4)
           SOCB R5,*R1+       superimpose it on char 2 (or 4)
           DEC  R3
           JNE  LHH0

           LI   R0,>08D0      address of pattern for char 26-29
           LI   R1,BUF2
           LI   R2,32
           BL   @VMBW1        set their patterns
           MOV  @SCPOS,R0     display char 26-29 at cursor position
           LI   R1,SPCH
           BL   @PUT4CH
           B    *R9          
    * This routine erases the cursor displayed by the above
    NOCUR  MOV  R11,R9
           MOV  SCPOS,R0      screen position of the cursor
           LI   R1,BUF1       buffer where the 4 chars were saved
           MOV  *R1,*R1       but were they?
           JEQ  SK1           not yet: no cursor on screen
           BL   @PUT4CH       restore them
           CLR  @BUF1         flag: no cursor on screen
    SK1    B    *R9
    SCPOS  DATA 0             current screen address of the cursor
    SPROW  DATA 0             pixel row for the cursor
    SPCOL  DATA 0             pixel column for the cursor
    BUF1   DATA 0,0           buffer for 4 chars
    BUF2   BSS  32            buffer for 4 char patterns
    SPCH   BYTE 26,28,27,29   characters that make up the cursor
    PATRN  DATA >2020,>F820,>2000,>0000  cursor pattern
    H0028  DATA >0028         constant: 40 columns
    H0006  DATA >0006         constant: 6 pixels

    Revision 1. 6/20/99. Ok to release

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