AS1122
Datasheet ꢀ Detailed Description
Register Access
Before data are accepted by the AS1122, an identifier needs to be send in advance. Only 3 defined identifiers will be recognized, all other bit
combinations will be ignored.
Table 6. Identifier
Bit
Data Section
Identifier
Description
length
7
1
1
1
6
1
1
1
5
0
0
0
4
0
0
0
3
2
0
0
1
1
0
1
0
0
1
0
0
Dot Correction Data
PWM Data
1 / 0
1 / 0
1 / 0
72 bits
144 bits
8 bits
writes Data into Dot Correction Register
writes Data into PWM Register
Command Data
writes Data into Command Register
The identifier maps the input register to the identified register and all data on pin SDI will be clocked into this register. This selection is valid as
long as no internal LD signal is triggered. When data is latched into the device the identifier selection is reset and for the next data word a new
identifier needs to be send. Every identifier requires a certain data section length. If this length is not corresponding with the identifier, the data
will be ignored.
Note: Bit3 of the identifier is an global on/off bit. When bit3 of any identifier is set to logic ‘0’ and the OEN bit of the command register (see
Figure 7 on page 14) is ‘0’ (per default), the output channels are immediately turned on.
Dot Correction (DC)
The AS1122 offers a 6 bit (64 steps) Dot Correction per Output channel. After sending the 8 bit identifier for access to the DC register the device
is waiting for 72 bits to receive. If more or less bits are send the whole dataword will be ignored.
Figure 25. Dot Correction Input Timing Diagram
For n devices in a chain only one identifier needs to be send to set all n devices to the same register setting.
Figure 26. Dot Correction for n-devices
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