Altera Video and Image Processing Suite - Manual (Page 216)

Signal Direction Description
gamma_lut_av_write
Input
gamma_lut
slave port Avalon-MM
write
signal. When
you assert this signal, the
reader control
port accepts
new data from the
writedata
bus.
gamma_lut_av_writedata
Input
gamma_lut
slave port Avalon-MM
writedata
bus. The IP
core uses these input lines for write transfers.
Gamma Corrector Control Registers
The Gamma Corrector can have up to three Avalon-MM slave interfaces.
There is a separate slave interface for each channel in parallel.
The control registers are read continuously during the operation of the IP core, so making a change to
part of the Gamma look-up table during the processing of a frame always has immediate effect.
Note: The width of each register in the Gamma Corrector control register map is always equal to the
value of the Bits per pixel per color plane parameter selected in the parameter editor.
When dealing with image data with N bits per pixel per color plane, the address space of the Avalon-MM
slave port spans 2 N + 2 registers where each register is N bits wide. Registers 2 to 2 N + 1 are the look-up
values for the gamma correction function. Image data with a value x will be mapped to whatever value is
in the LUT at address x + 2.
Table 15-3: Gamma Corrector Control Register Map for Interface 0
Address Register Description
0
Control
Bit 0 of this register is the
Go
bit, all other bits are unused.
Setting this bit to 0 causes the IP core to stop the next time
control information is read.
1
Status
Bit 0 of this register is the
Status
bit, all other bits are unused.
2 to 2 N +1
where N is the
number of bits
per color
plane.
Gamma Look-Up Table
These registers contain a look-up table that is used to apply
gamma correction to video data. An input intensity value of x
is gamma corrected by replacing it with the contents of the (x
+1)th entry in the look-up table. Changing the values of these
registers has an immediate effect on the behavior of the IP
core. To ensure that gamma look-up values do not change
during processing of a video frame, use the
Go
bit to stop the
IP core while the table is changed.
Table 15-4: Gamma Corrector Control Register Map for Interface 1
Address Register Description
0
Unused
This register is not used.
1
Unused
This register is not used.
UG-VIPSUITE
2015.05.04
Gamma Corrector Control Registers 15-3
Gamma Corrector IP Core Altera Corporation
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