Spectrum QL
Contents
Spectrum QL
The Sinclair QL (for Quantum Leap) is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the ZX Spectrum. It was aimed at the serious home user and professional and executive users markets from small to medium-sized businesses and higher educational establishments, but failed to achieve commercial success. The Sinclair QL uses a Motorola 68008.CPU with 32-bit internal data registers, but an 8-bit external data bus.
Setting up
- Assembler: VASM
- Emulator(s): Q-emulator ( http://www.terdina.net/ql/winql.html )
- Hardware:
In order to test the final result one can use a floppy-disk replace replacement or Qubide interface to load files from SD card.
Memory map
$00000 Onboard 48k Rom
$0C000 16K Rom Cartridge
$10000 Onboard I/O
$18000 (R) RTC byte 0 / (W) RTC Reset
$18001 (R) RTC byte 1 / (W) RTC Step
$18002 (R) RTC byte 2 / (W) Transmit control
$18003 (R) RTC byte 3 / (W) IPC link control
$18020 (R) Microdrive/RS232c status / (W) Microdrive control
$18021 (R) Interrupt/IPC status / (W) Interrupt control
$18022 (R) Microdrive Track 1 / (W) Microdrive / RS232C data
$18023 (R) Microdrive Track 2 / (W) Display control
$18063 Screen Mode S---C-O- On Colordepth Screenpage
$20000 Screen 1 Screen Ram
$28000 Screen 2 /
System system (systemvars*)
$2847C System stack pointer*
$28E00 Base of Common Heap*
$2BC00 Free area*
$30000 Running Programs Free area
$37200 Basic area*
$38000 User Stack pointer*
$38000 Prog data*
$40000 Add on ram (up to 512k)
$C0000 Add on peripherals
$E0000 Add on Rom (up to 128k)
$FFFFF End of address spaceVideo display
There are two possible screen modes, configured by bit 3 of port $18063
setting a 0 give 4 colors at 512x256 with Black,Red,Green and White setting a 1 give 8 colors at 256x256 with Black, R, G B, C, M, Y and White
The Screen is memory mapped from $20000-$28000, There is no palette - the colors are fixed.
Vsync
Port $18021 bit 3 will go high (1) when Vsync starts, then we need to write a 1 to that same bit at the same port to clear the Vsync event. Therefore, in effect we can write 255 to port $18021, then read from $18021 until it's nonzero to get the Vsync event.
move.b #%11111111, $18021 ; Clear interrupt bits
waitvbl:
move.b $18021,d0 ; Read in interrupt state
tst.b d0 ; Wait for an interrupt
beq waitvblPlotting to screen
To be addedSound
The Spectrum QL has 2 channels of internal beeped sound, or AY support via an extension board.
Speaker Sound commands have to be passed via the Bios, using the same kind of commands as with the keyboard. You need to adjust the Pitch settings to change the sound, and you can change the randomness bits to make the sound distorted, It seems it's not possible to change the volume!
