TS68230
HMOS PARALLEL INTERFACE/TIMER
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TS68000 BUS COMPATIBLE
PORT MODES INCLUDE :
BIT I/O
UNIDIRECTIONAL 8 BIT AND 16 BIT
BIDIRECTIONAL 8 BIT AND 16 BIT
PROGRAMMABLE HANDSHAKING OPTIONS
24-BIT PROGRAMMABLE TIMER MODES
FIVE SEPARATE INTERRUPT VECTORS
SEPARATE PORT AND TIMER INTERRUPT
SERVICE REQUESTS
REGISTERS ARE READ/WRITE AND DIRECTLY ADDRESSABLE
REGISTERS ARE ADDRESSED FOR MOVEP
(Move Peripheral) AND DMAC COMPATIBILITY
1
P
(PDIP48)
FN
(PLCC52)
PIN CONNECTIONS
DESCRIPTION
The TS68230 parallel interface/timer (PI/T) provides
versatile double buffered parallel interfaces and a
system oriented timer for TS68000 systems. The parallel interfaces operate in unidirectional or bidirectional modes, either 8 or 16 bits wide. In the
unidirectional modes, an associated data direction
register determines whether each port pin is an input
or output. In the bidirectional modes the data direction registers are ignored and the direction is determined dynamically by the state of four handshake
pins. These programmable handshake pins provide
an interface flexible enough for connection to a wide
variety of low, medium, or high speed peripherals or
other computer systems. The PI/T ports allow use of
vectored or auto-vectored interrupts, and also provide a DMA request pin for connection to the 68440
direct memory access controller (DMAC) or a similar
circuit. The PI/T timer contains a 24-bit wide counter
and a 5-bit prescaler. The timer may be clocked by
the system clock (PI/T CLK pin) or by an external
clock (TIN pin), and a 5-bit prescaler can be used. It
can generate periodic interrupts, a square wave, or
a single interrupt after a programmed time period. It
can also be used for elapsed time measurement or
as a device watchdog.
January 1989
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