Glossary
The technical terms of this wiki, in alphabetical order, with a pointer to the page that says the most about each.
On this page
6502 · The Oric’s 8-bit processor, in its NMOS version, at 1 MHz. See The 6502 core.
ACIA · Asynchronous Communications Interface Adapter: a serial port chip. The 6551 (MOS) and the 6850 (Motorola) are emulated.
Aliasing · A sound too high for the sampling rate, which comes out at a false frequency. Avoided in Phosphoric by the integrated output.
Blanking · The part of the line or frame where the beam draws nothing. On the Oric, counts 40 to 63 of each line.
Cell · A group of 6 horizontal pixels, read by the ULA in one cycle. A line has 40 of them.
Chunky · A graphics mode where each pixel has its own colour (here 4 bits, 16 colours), as opposed to the Oric’s attributes. Offered by the ULA-NG.
Colour clash · The Oric’s constraint whereby changing colour costs a cell and cannot happen in the middle of a character.
Copper · A list of changes (here palette changes) applied line after line, during the scan. The name comes from the Amiga.
Cycle · One microsecond on the Oric: one 6502 bus access, then one ULA read.
Cycle-stepped · Said of an emulated machine whose chips all move together, one cycle at a time. That is Phosphoric since 2.0; only its processor is called “exact to the cycle”.
DTL 2000 · A V23 modem card from Digitelec, for the Minitel and videotex.
Dummy access · A bus access the NMOS 6502 makes without needing it, in the middle of an instruction: re-read, read before indexing, write-back before modification. On an I/O register, it has effects. See Accuracy, word by word.
Emulator · A program that reproduces a machine and its chips in software, to run the original software on it.
Frame · A full picture: 312 lines, 19,968 cycles, 50 per second.
HFE · A magnetic floppy image format, read by the HxC, Gotek and Greaseweazle drive emulators.
HIRES · The Oric’s graphics mode: 240 × 200 pixels, plus 3 rows of text.
IJK · A joystick adapter for the Oric, plugged into the PSG’s port A.
JAM · Twelve NMOS 6502 opcodes that lock the processor. Phosphoric stops the emulation.
LOCI · Lovely Oric Computer Interface: a modern RP2040 cartridge that brings storage, USB, a modem and a menu. See The LOCI.
LOCI-USB · A LOCI without the Oric interface, connected to the host over USB; Phosphoric plays the part of the Oric.
Master clock · In Phosphoric, emu_cycle(): one call moves the whole machine one cycle forward. See
The master clock.
MFM · The magnetic encoding of the Oric’s floppies. MFM_DISK is the .dsk image format that keeps
their tracks.
MIA · The LOCI’s register block at $03A0-$03BF, through which the Oric calls the cartridge’s API.
Microdisc · A floppy interface for the Oric, with a WD1793 controller.
N1, N2, N3, N4 · Phosphoric’s four accuracy levels: counted per instruction, ordered per bus cycle, stepped per cycle, below the cycle. See Accuracy, word by word.
NMI · An interrupt the processor cannot mask. On the Oric, the button under the machine; in Phosphoric, Shift + F5.
NMOS · The technology of the first generation of the 6502, with its dummy accesses and illegal opcodes, as opposed to the 65C02 (CMOS).
Oracle · An external reference that says what should be obtained. For the 6502: SingleStepTests/65x02, with the expected bus trace cycle by cycle.
.ost · Phosphoric’s save state format.
Page 3 · Addresses $0300 to $03FF, reserved for input and output. See Page 3 and the
cards.
Parallel attributes · In the ULA-NG, a separate memory plane that gives each cell’s ink and paper, with no serial attribute. They remove colour clash.
Penultimate cycle · The second-to-last cycle of an instruction, during which the 6502 looks at its interrupt lines.
PHI2 (φ2) · The second phase of the 6502’s clock, during which bus transfers happen.
PSG · Programmable Sound Generator: the Oric’s AY-3-8912. See Sound.
Raster split · A change made while the beam scans the screen, which cuts the picture in the middle of a line. See The picture and the ULA.
ROM · The Oric’s read-only memory: its BASIC, 16 KB. The ROMs are not supplied with Phosphoric.
Sedoric · A disk operating system for the Oric. See Tapes, floppies and save states.
Serial attribute · A screen byte that does not show as a character but changes the ink, paper, style or mode for the rest of the line. See The emulated Oric.
Sprite · A small drawing composed by the video chip over the screen, without touching its memory.
.tap · The Oric’s tape format.
ULA · Uncommitted Logic Array: the Oric’s chip (HCS 10017) that makes the picture and shares memory with the 6502. See The picture and the ULA.
ULA-NG · Phosphoric’s extended ULA, locked at start-up, reference of a future FPGA chip. See The ULA-NG.
V23 · The Minitel’s modem standard: 1,200 baud one way, 75 the other.
VDU · A stream of display commands, in the manner of the BBC Micro. The ULA-NG interprets one.
VIA · Versatile Interface Adapter: the Oric’s 6522, two ports and two timers.
VSYNC hack · A hardware modification of the Oric, a wire from the ULA to the VIA, that makes the start of the frame visible. Not emulated.
WD1793 · The Microdisc’s floppy controller.
WebAssembly · The code format browsers run; Phosphoric’s web version is made of it. See In the browser.
Zero page · The first 256 addresses of memory, which the 6502 addresses faster.