UM6522/A
Versatile Interface Adap ter( VIA)
Features
. Two Shit bi-directional I/O ports
n
Two 16-bit programmable timer/counters
m Serial data port
n
Single +5V power supply
m TTL compatible except Port A
n
CMOS compatible peripheral Port A lines
m Expanded “handshake” capability allows positive
control of data transfers between processor and periph-
eral devices
n
Latched input and output registers
n
1 MHz and 2 MHz Operation
General Description
The UM6522/A Versatile Interface Adapter (VIA) is a very
flexible l/O control device. In addition, this device con-
tains a pair of very powerful 16.bit interval timers, a serlal-
to-parallel/parallel-to-serial shift register and input data
latching on the peripheral ports. Expanded handshaking
capability allows control of bi-directional data transfers
between VIA’s in multiple processor Systems.
Control of peripheral devices is handled primarily through
two Shit bi-directional ports. Esch line tan be program-
med as either an input or- an output. Several peripheral
l/O lines tan be controlled directly from the interval timers
for generating programmable frequency Square waves or
for counting externally generated Pulses.
To facilitate
control of the many powerful features of this Chip, an
interrupt flag register, an interrupt enable register and a
pair of function control registers are provided.
Pin Configuration
Block Diagram
“SS c
PA0 c
PA1 c
2
3
39
38
37
36
35
34
33
2
8
E
$
;:
30
29
28
27
26
25
24
23
22
21
PA2 r 4
PA3 c 5
PA4 c 6
PA5 c 7
PA6 c 8
PA7 [z
PB0 c
PB1 c
9
‘O
11
13
14
15
16
17
16
19
20
] CA1
] CA2
-J RSO
] RSl
] RS2
] RS3
]RES
1 DO
1 D’
1
D2
I] D3
2 D4
7 D5
7
PB2 [ ‘12
PB3 [
PB4 c
PB5 [
D6
7 07
7 $2
7 CS1
Jcs2
PB6 c
PB7 [I
CB1 c
CB2 c
“cc c
5-18
UMC [ UMC CORPORATION ]
