ICS5342 Datasheet, PDF (4/36 Pages) Integrated Circuit Systems – 16-Bit Integrated Clock-LUT-DAC

ICS5342
GENDAC
Internal Registers
RS2
RS1
RS0
0
1
1
0
1
1
0
0
1
0
1
0
1
0
0
1
1
1
Register Name
Description (all registers can be written to and read from)
The GENDAC has a single pixel address register which can be
accessed through either register address 0,0,0 or 0,1,1 – reading
from either register gives the same result.
Pixel Address
WRITE
Pixel Address
READ
Color Value
Writing a value to address 0,0,0:
– specifies an address within the color palette RAM
– initializes the Color Value register
Writing a value to address 0,1,1:
– specifies an address within the color palette RAM
– loads Color Value register with contents of location in
addressed RAM palette and then:
– increments Pixel Address register
Writing to this 8-bit register is done before writing one or more
color values to color palette RAM.
Writing to this 8-bit register is done before reading one or more
color values from color palette RAM.
The 18-bit Color Value register acts as a buffer between the
microprocessor interface and the color palette. A value may be
read from or written to this register using a three-byte transfer
sequence. The color value is contained in the least significant 6
bits, D0-D5, of the byte read – the most significant 2 bits are set
to zero. The same 6 bits are used when writing a byte. When
reading or writing, data is transferred in the same order – red
byte first, then green, then blue. Each transfer between the Color
Value register and the color palette replaces the normal pixel
mapping operations of the GENDAC for a single pixel.
After writing three definitions to this register, its contents are
written to the location in the color palette RAM specified by the
Pixel Address register, before that register increments.
Pixel Mask
PLL Address
WRITE
PLL Address
READ
After reading three definitions from this register, the contents of
the location in the color palette RAM specified by the Pixel
Address registers are copied into the Color Value register, and
the Pixel Address register increments.
The 8-bit Pixel Mask register can be used to mask selected bits
of the Pixel Address value applied to the Pixel Address inputs
(P7-P0). A one in a position in the mask register leaves the corre-
sponding bit in the Pixel Address unaltered, while a zero sets
that bit to zero. The Pixel Mask register does not affect the Pixel
Address generated by the microprocessor interface when the pal-
ette RAM is being accessed.
Writing to this 8-bit register is performed prior to writing one or
more PLL programming values to the PLL Parameter register.
Writing to this 8-bit register is performed prior to reading one or
more PLL programming values from the PLL Parameter register.
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