Hi expert,
My customer asked us pattern generator w/ external timing mode.
According to datasheet of DS90UH929, user should refer "snla132c.pdf" about how to use pattern generator.
And, here is my understanding about "external timing mode" of pattern generator. If my understanding is NOT correct, could you correct me ?
- 1 -
For connection b/w 929 and source :
1.1. User should connect only CLK+/- from source to 929.
1.2. User can NOT set blanking period, because pattern generator of 929 can NOT detect VS.(blanking period depends on CLK+/-.)
In case of DS90UB/UH925, when user will use external timing mode, user can input PCLK, DE and VS respectively and Data(RGB) is generated by Pattern generator.
However, in case of HDMI(DS90UB/UH929), signal from channel0 (Pin names of DS90UH929 are "In_D0+" and ""In_D0-") are recovered Data(one of R,G or B) and sync by TMDS decorder. In other words, user can NOT input Data and VS respectively.
Therefore, if user want to control blanking period by VS, user have to input D0+/- in addition to CLK as well.
(I believe that 929 does NOT allow mentioned above)
- 2 -
For register setting :
To enable "external timing mode" of pattern generator, user should set only following two registers.
2.1. Set "Timing select" bitfield of Pattern Generator Configuration（Addr:0x65）to "0x0"
2.2. Set "Pattern Generator Enable" bitfield of Pattern Generator Control（Addr:0x64）to "0x1"
If there is no specific requirement, other registers can be left default.
Best Regards,
Machida
