Flash Rom; Realtime Clock - David Griffith P112 Assembly And Operation Manual

Function
Parallel Port
Diskette (program access)
Serial Port
Diskette (DMA Access)
8.3

Flash ROM

The board is designed to program a variety of flash ROM parts. If 5V-only parts
(eg Atmel) are used, the voltage converter U12 and its associated components
may be omitted.
8.4

Realtime Clock

A Dallas DS1302 realtime clock/RAM is used. This has a serial interface, which
is implemented using 3 spare parallel-port pins from the CPU chip.
Be aware that this chip, when first powered-up, defaults to write-protected and
oscillator disabled. Before it will run normally, you must first turn off write-
protect, then activate the oscillator. Each is a single-byte write operation.
Address (CPU) Address (IO Chip)
8C. . .8F 3BC. . .3BF
90. . .97 3F0. . .3F7
98. . .9F 3F8. . .3FF
A0. . .BF N/A
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