TS68230 Datasheet, PDF (1/61 Pages) STMicroelectronics – HMOS PARALLEL INTERFACE/TIMER

TS68230
HMOS PARALLEL INTERFACE/TIMER
.. 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 DIRECT-
LY ADDRESSABLE
. REGISTERS ARE ADDRESSED FOR MOVEP
(Move Peripheral) AND DMAC COMPATIBILITY
1
P
(PDIP48)
FN
(PLCC52)
DESCRIPTION
The TS68230 parallel interface/timer (PI/T) provides
versatile double buffered parallel interfaces and a
system oriented timer for TS68000 systems. The pa-
rallel interfaces operate in unidirectional or bidirectio-
nal 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 direc-
tion registers are ignored and the direction is deter-
mined 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 pro-
vide 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
PIN CONNECTIONS
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