TLC34075-135FN Datasheet, PDF (30/52 Pages) Texas Instruments – Video Interface Palette Data Manual

2.12 Test Register
There are three test functions provided in the TLC34075, and they are all controlled and monitored through
the test register. They are data flow check, DAC analog test, and screen integrity test.
The test register has two ports: one for a control word, accessed by writing to the register location, and one
for the data word, accessed by reading from the register location. Depending on the channel written in the
control word, the data read presents the information for that channel.
The control word is three bits long and occupies D<2:0>. It specifies which of the eight channels to inspect.
The following table and state machine diagrams show how each channel is addressed:
Table 9. Test Mode Selection
D2 D1 D0
CHANNEL
0 0 0 Color palette red value
0 0 1 Color palette green value
0 1 0 Color palette blue value
0 1 1 Identification code
1 0 0 Ones accumulation red value
1 0 1 Ones accumulation green value
1 1 0 Ones accumulation blue value
1 1 1 Analog test
ID code
011
RD
2–18
RESET
000
Red
RD
RD
010 _Blue
RD
001 _Green
Data Flow Check
RD
111
DAC Analog Test
Red
Blue
RD
100
110
RD
RD
101 _Green
Screen Integrity Test
Figure 13. Test Register Control Word State Diagrams