ics9161a Integrated Device Technology, ics9161a Datasheet - Page 3

• Manufacturer Part Number: ics9161a
• Description: Dual Programmable Graphics Frequency Generator
• Manufacturer: Integrated Device Technology

Register Definitions
The register file consists of the following six registers:
The ICS9161A places the three video clock registers and
the memory clock register in a known state upon power-
up. The registers are initialized based on the state of the
INIT1 and INIT0 pins at application of power to the device.
The INIT pins must ramp up with VDD if a logical 1 on either
pin is required. These input pins are internally pulled down
and will default to a logical 0 if left unconnected.
The registers are initialized as follows:
Register Selection
When the ICS9161A is operating, the video clock output
is controlled with a combination of the SEL0, SEL1, PD#
and OE pins. The video clock is also multiplexed to an
external clock (EXTCLK) which can be selected with the
EXTSEL pin. The VCLK Selection Table shows how VCLK
is selected.
0210I—03/21/05
O
A (
N I
A
0
1
1
1
1
1
1
E
d
0
0
2
1
1
T I
0
0
1
1
0
0
d
0
1
0
1
0
1
-
e r
1
0
0
0
0
1
1
A
P
s s
) 0
D
x
0
1
1
1
1
1
#
N I
R
R
R
M
P
C
0
0
T I
1
1
E
E
E
W
N
R
0
R
G
G
G
E
T
E
R
Register Initialization
Register Addressing
e
X
L
0
1
2
G
D
g
T
R
VCLK Selection
W
x
x
x
x
0
x
t s i
1
4
3
5
5
S
M
E
2
0
0
6
N
E
r e
R
G
5 .
0 .
3 .
6 .
L
E
0
0
5
4
G
0
0
0
4
M
D
C
V
V
V
S
d i
d i
d i
v i
o
e
2
2
4
4
R
E
n
m
s i
x
x
0
0
e
e
e
5
5
0
0
1
1
1
r t
E
L
o
o
o
1 .
1 .
0 .
0 .
o
o
l o
1
G
f r
y r
C
C
C
7
7
0
0
0
5
5
0
0
R
o l
o l
o l
r o
R
S
e
k c
k c
k c
D
e
E
P
g
x
x
0
0
x
1
1
g
L
f e
t s i
o
2
2
2
5
R
R
R
R
t s i
0
w
8
8
8
0
n i
e
e
e
r e
E
3 .
3 .
3 .
3 .
r e
r e
t i
g
g
g
G
2
2
2
5
o i
F
t s i
t s i
t s i
d -
1
2
2
2
0
o
E
n
o
r e
r e
r e
r T
c r
V
R
R
R
R
X
w
s i
e
C
E
T
E
E
E
n
1
2
3
2
2
2
5
d
a t
R
C
L
G
G
G
G
8
8
8
0
m
K
H
L
E
e t
0
2
2
1
3 .
3 .
3 .
3 .
K
o
g i
G
d
2
2
2
5
h
2
2
2
2
0
e
3
The Clock Select pins SEL0 and SEL1 have two purposes.
In serial programming mode, these pins act as the clock
and data pins. New data bits come in on SEL1 and these
bits are clocked in by a signal on SEL0. While these pins
are acquiring new information, the VCLK signal remains
unchanged. When SEL0 and SEL1 are acting as register
selects, a time-out interval is required to determine whether
the user is selecting a new register or wants to program the
part. During this initial time-out, the VCLK signal remains
at its previous frequency. At the end of this time-out
interval, a new register is selected. A second time-out
interval is required to allow the VCO to settle to its new
value. During this period of time, typically 5ms, the input
reference signal is multiplexed to the VCLK signal.
When MCLK or the active VCLK register is being re-
programmed, then the reference signal is multiplexed
glitch-free to the output during the first time-out interval. A
second time-Register out interval is also required to allow
the VCO to settle. During this period, the reference signal
is multiplexed to the appropriate output signal.
As seen in the VCLK Selection table, OE acts to tristate
the output. The PD# pin forces the VCLK signal high while
powering down the part. The EXTCLK pin will only be
multiplexed in when EXTSEL and SEL0 are logic 0 and
SEL1 is a logic 1.
The memory clock outputs are controlled by PD# and
OE as follows:
O
0
1
1
E
MCLK Selection
P
D
x
0
1
#
ICS9161A
P
r T
W
M
M
s i
R
R
C
a t
D
E
L
K
G
W
e t
N