The Hegotron Grafpad II is a graphic tablet from British Micro - A Hegotron Group Company, marketed by Grafsales Ltd. It was produced for the Amstrad CPC, Joyce PCW and the IBM PC.
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This device is supported by FutureOS. The resolution of about 1500 * 1000 points is used.
Pictures
- GrafPad II
Top
Matrix
Bottom
Template
Interface PCB Top
Interface PCB Bottom
Pen PCB Top
Pen PCB Bottom
Commercials
- Grafpad II
Grafpad II for BBC, Amstrad, C64 (Grafsales) (as advertised in ACU Dec 1985)
Grafpad I for BBC, Spectrum, C64 (British Micro / Hegotron)
Preview in Greek Side of Amstrad magazine
Advertisement in Amstrad Computer User
Reviews
The Grafpad II is reviewed in Amstradbladet 1987, Issue 4, page 24 (Danish)
Source Code
The following routines and descriptions are a part of FutureOS. All rights remain by Dr. Stefan W. Stumpferl. Free for non-commercial / private use. If you want to use this routines or parts of them, then give credits to TFM of FutureSoft! The original Hegotron software uses other port addresses and routines. This solution is faster and compatible to all other tested hardware expansions, which is not the case for the original routines from Hegotron. Version: 24.09.2010 - TFM of FutureSoft aka Dr. Stefan W. Stumpferl Questions? Mail me: FutureSoft@gmx.de ;TEST IF HEGOTRON GRAFPAD 2 IS CONNECTED ; ;Parameters given back ; ;A = (&00 and) Z-Flag is set ---> no GP2 connected ; = (&01-05,) Z-Flag cleared --> GP2 is connected ; ;Manipulated AF, BC T_GP2 LD A,&02:LD BC,&F9F7:OUT (C),A:LD C,&FF:OUT (C),C:LD C,&F7:IN A,(C):INC A:RET TEST IF HEGOTRON GRAFPAD 2 IS CONNECTED ======================================= Short description: Test if the Hegotron Grafpad 2 is connected. Jump in conditions: - Jump out conditions: The Z80 register A reports if the Hegotron Grafpad 2 is connected to the CPC or not. A = &00 and zero flag is set ------> NO GP2 connected. A = &01-05 and zero flag cleared --> the GP2 IS connected. Manipulated: AF and BC. Description: This routine tests if the Grafpad 2 from Hegotron is connected to the CPC. You call the routine without any parameters. After the return of T_GP2 the Z80 register A and the zero flag report about the existence of the Grafpad 2. If the routine returns with the value &00 in register A and with a set zero flag, then the Grafpad 2 can't be found. Else if the routine returns with A unqual to &00 and with a cleared zero flag, then the Grafpad 2 is connected. Example: CALL T_GP2;test if Grafpad 2 is connected. JR Z,NO_GP2 ;NO GP 2 connected! GP2 ... ;the GP2 IS connected! ... ... ;SCANNING OF THE HEGOTRON GRAFPAD 2 ; ;Parameters given back ; ;DE = Y coordinate &0000-&04FF (&001B-&0484) ;HL = X coordinate &0000-&05FF (&0020-&05DF) + Buttons E (7.Bit H), S (6.Bit H) ;Bit 7/6(H) = 0 --> key pressed, Bit = 1 --> NO key pressed ; ;Manipulated AF, BC, DE, HL, BC' G_GP2 XOR A,A:LD BC,&F9F7:OUT (C),A ;OUT &F9F7,&00 EXX:LD BC,&F9FF:OUT (C),C:EXX ;OUT &F9FF,&FF IN E,(C) ;yl=INP(&F9F7) INC A:OUT (C),A:EXX:OUT (C),C:EXX:IN L,(C) ;xl INC A:OUT (C),A:EXX:OUT (C),C:EXX:IN D,(C) ;yh INC A:OUT (C),A:EXX:OUT (C),C:EXX:IN H,(C) ;xh RET SCANNING OF THE HEGOTRON GRAFPAD 2 ================================== Short description: Scanning of the X-, the Y-coordinates and both buttons (E and S) of the Hegotron Grafpad 2. Jump in conditions: - Jump out conditions: The registers DE and HL report about the X- and the Y-coordinates and the buttons E and S. DE = Y-coordinate, theoretical: &0000-&04FF, in real: &001B-&0484 HL = X-coordinate, theoretical: &0000-&05FF, in real: &0020-&05DF And register H contains the state of the buttons E (bit 7, MSB of H) and S (bit 6 of H). For both buttons is valid, that a cleared bit reports a pressed key. If a bit is set, the key is NOT pressed. Manipulated: AF, BC, DE, HL and BC' Description: If the CPC is connected to the Hegotron Grafpad 2 (you MUST test this before!), then you can use this routine G_GP2 to scan the actual coordinates of the graphic table pen and the status of the buttons. When the routine returns DE contains the Y-coordinate of the pen. Theoretically that can be a value between &0000 and &04FF. But in reality the graphic tablet covers values between &001B and &0484. (There can be differences between different units). Little Y values are located at the bottom, near the user. Big Y values are located upwards, away from the user. The register HL reports about the X coordinate (bits 0-10) and the status of the buttons. The X coordinate theoretical spans over values from &0000 up to &05FF. In reality the values lie between &0020 and &05DF. Little X values are located left, big X values are located right on the graphic tablet. Further the most upper bits of register H (7 and 6) contain the status of both buttons of the GP2. H encodes the buttons E (bit 7) and S (bit 6): - If bit 7 is cleared to 0, the key E (Entry, Exit) IS pressed now. If bit 7 is set to 1, the key E is actually NOT pressed. - If bit 6 is cleared to 0, the key S (Select) IS pressed now. If bit 6 is set to 1, the key S is actually NOT pressed. Example: CALL G_GP2 ;get Grafpad 2 coordinates and buttons. LD (GP2_X_Koordinate),DE ;save X-coordinate into RAM LD A,H AND A,&C0 ;isolate bits 7 and 6 (= keys E and S), LD (KEYS_E_AND_S),A) ;and save key status (??00 0000) to RAM RES 7,H RES 6,H LD (GP2_Y_Koordinate),HL ;save Y-coordinate into RAM ... Attention: Use this routine ONLY if you are sure that the Grafpad 2 IS connected to the CPC. Use T_GP2 to test this (look before). ;SCANNING OF THE BUTTONS E AND S OF THE HEGOTRON GRAFPAD 2 ; ;Parameters given back ; ;A (Bit 7) = button E / valid is... ;A (Bit 6) = button S / Bit = 0 --> key pressed, Bit = 1 --> NO key pressed ; ;Manipulated AF, BC K_GP2 LD A,&03:LD BC,&F9F7:OUT (C),A:LD C,&FF:OUT (C),C:LD C,&F7:IN A,(C) ;yh INC A:RET SCANNING OF THE BUTTONS E AND S OF THE HEGOTRON GRAFPAD 2 ========================================================= Short description: Keys E and S of the Hegotron Grafpad 2 are scanned. Label: K_GP2 ROM-number: D Start address: &E73E Jump in conditions: - Jump out conditions: The register A reports if one of the two buttons E (Entry, Exit) and / or S (Select) is pressed. Register A bit 7 corresponds to key E. Register A bit 6 corresponds to key S. A cleared bit (0) symbolizes a pressed key, whereas a set bit (1) symbolizes that the key is NOT pressed. Manipulated: AF and BC. Description: If the CPC is connected to the Hegotron Grafpad 2 (you must test this before!), you can use this routine K_GP2 to investigate the status of both keys. After the return of the routine the status of the keys is encoded in the two upper bits of register A; key E (bit 7) and key S (bit 6): - If bit 7 is cleared to 0, the key E (Entry, Exit) IS pressed now. If bit 7 is set to 1, the key E is actually NOT pressed. - If bit 6 is cleared to 0, the key S (Select) IS pressed now. If bit 6 is set to 1, the key S is actually NOT pressed. Example: CALL K_GP2 ;scan Grafpad 2 keys AND A,&C0 ;isloate bits 7 and 6 (??00 0000) LD (KEYS_E_AND_S),A) ;and save status of keys to RAM ... Attention: Use this routine ONLY if you are sure that the Grafpad 2 IS connected to the CPC. Use T_GP2 to test this (look before).
Manual
Downloads
The System Software can be found here: