ACM100
Figure 13. Q Threshold Selection
Fixed Slope Settings
Max Q = 512
Min Q = 16
Slope = -2
0
MUX
1
Drawing Engine
Defaults:
Max Q = 512
Min Q = 16
Slope = -2
1
0
Note polarity of
this mux
MUX
User Table
Loaded over I2C
Register 0x0C
Defaults: Unknown
The first two methods assume that the Q function has a specific shape defined by Max Q, Min Q and Slope parameters resulting
in a Q function as shown in Figure 14.
Figure 14. Standard Threshold Shape
Max Q
Slope
Min Q
0
511
Gray Shade
The alternative is to manually load a table which will specify a unique Q value for each gray level. The bits are defined as follows:
[15:14] Reserved:
These bits are reserved for future use and should not be set. To ensure compatibility with future
releases, we recommend using a read/modify/write operation to preserve the status of these bits.
Writing a ‘0’ to this bit will enable the use of a user loaded curve. This must be loaded via register
0x15 prior to enabling this function. [12] Draw_En Writing a ‘1’ to this bit will enable a Q function
based on the parameters programmed in registers 0x3 and 0x5.
[13]User_Curve_En:
The Min Q field specifies the Q value at which the function will level off. The Q value for gray shade
zero is set to the max Q value and then decremented by the Q Slope until this value is reached. Note:
if the Min_Q value is set to be higher than the Max_Q value, the result will be a flat threshold at the
Min_Q value.
[11:0] Min_Q
Document Number: 001-05325 Rev. **
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