
June 1997
17
ADVANCE DATA BOOK v2.0
PIN DESCRIPTIONS
CL-PS7500FE
System-on-a-Chip for Internet Appliance
VIREF
IA
VIDEO REFERENCE CURRENT:
The video DACs need a refer-
ence current to calibrate them. A constant current source is recom-
mended, although a resistor up to V
DD
is sufficient for many
applications. This current also generates the constant source for the
A-to-D comparators.
VSYNC
OCZ
3
VERTICAL SYNCHRONIZATION:
Dependent on the state of bits
19 and 18 in the external register, either a vertical or a composite
(XNOR) sync can be output on this pin, in either polarity. The width
of the
VSYNC
pulse can be defined in units of a raster.
WS
OCZ
2
WORD SELECT:
This signal denotes whether the output serial data
is for the left-hand or right-hand stereo channel.
nTEST
IT
TEST MODE INPUT:
This pin should be held permanently high. It
is only intended to be used during production test of the
CL-PS7500FE. An on-chip pull-up resistor is included, but it is
advised to apply an external pull-up resistor to this pin.
nWE
OCZ
2
WRITE ENABLE:
This is a active-low signal.
RA[11:0]
OCZ
2
DRAM ROW/COLUMN MULTIPLEXED ADDRESS BUS:
Addresses for this bus are decoded from the ARM processor
address for normal memory accesses, and are generated by the
DMA controller for DMA.
nRAS[3:0]
OCZ
3
DRAM ROW ADDRESS STROBES:
Each of these selects one of
the four banks of DRAM available.
nCAS[3:0]
OCZ
3
DRAM COLUMN ADDRESS STROBES:
These select the byte
within the word for DRAM accesses.
ATOD[3:0]
IAOD
ANALOG-TO-DIGITAL:
These are the four A-to-D channel input
voltages.
ATODREF
IA
ANALOG-TO-DIGITAL REFERENCE:
This is the reference voltage
for the A-to-D converter comparators.
OSCPOWER
OCZ
1
OCILLATOR POWER:
This is the enable signal for the system oscil-
lator(s). When low, this signal can be used to disable the external
oscillator(s).
OSCDELAY
CSOD
1
OCILLATOR DELAY:
This signal requires an RC network to gener-
ate a fixed delay when restarting the system oscillator(s) on exit
from STOP mode.
2.1
CL-PS7500FE Pin Descriptions
(cont.)
Name
Type
Drive
Strength
Description