💾 ROM Loader
▼BASIC ROM
$A000–$BFFF (8 KB)
Drop file or click
Monitor ROM
$F800–$FFFF (2 KB)
Drop file or click
Character ROM
CHARGEN (2 KB)
Drop file or click
MEMORY MAP
$0000-
FFF RAM
$A000-$BFFF BASIC
$D000-$D3FF VIDEO
$DF00 KBD MATRIX
$FC00 ACIA
$F800-$FFFF MON
OHIO SCIENTIFIC
📼 Cassette
▼6850 ACIA Interface
Load tape file
000
ACIA STATUS
RDRF
TDRE
DCD
CTS
300 Baud (Kansas City Std)
🔊
⌨️ Keyboard Matrix Monitor
▶ROW LATCH ($DF00 write)
$FF = 11111111
No row selected
COLUMN READ ($DF00 read)
$FF = 11111111
No keys detected
SCAN RATE
0/sec
8×8 SWITCH MATRIX
| C0 | C1 | C2 | C3 | C4 | C5 | C6 | C7 | |
|---|---|---|---|---|---|---|---|---|
| R0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| R1 | 9 | 0 | : | - | LF | ESC | Q | W |
| R2 | E | R | T | Y | U | I | O | P |
| R3 | RUB | RET | CTL | A | S | D | F | G |
| R4 | H | J | K | L | ; | SLK | RPT | BRK |
| R5 | SHL | Z | X | C | V | B | N | M |
| R6 | , | . | / | SHR | SPC | · | · | · |
| R7 | · | · | · | · | · | · | · | · |
74LS75
Quad bistable latches hold row select • DIODES
Prevent ghosting • Active-low logic throughout🔧 CPU Debug
▶A
$00
X
$00
Y
$00
SP
$FD
PC
$0000
FLAGS
nv-bdIzc
CYCLES
0
DISASSEMBLY
MEMORY @ $
Power on to inspect memory