EMMA 02

FRED 1

I/O Map

The following table lists the main I/O definitions of the FRED 1

EF1 Group 1: hex keypad or punch card data ready
Group 3: tape data ready
EF2 Tape running / stopped
EF4 Tape error
OUT 1

Set I/O group
I/O group 1: Hex keypad & punch card
I/O group 2: TV
I/O group 3: Tape
OUT 2 Group 1: 1 = program mode, 2 = direct mode
Group 2: display type; 0 = TV off, 1 = 32x32, 2 = 64x16, 3 = 64x32
Group 3: bit 4 = program mode, bit 5 = direct mode, bit 6 = write mode
OUT 3 Group 3: bit 0 = 1 - run tape, bit 1 = 1 - sound on, bit 2 = sound
INP 0 Group 1: read byte from hex keypad or punch card
Group 3: read byte from tape