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SN65DSI84: DSI tuner questions

Part Number: SN65DSI84
Other Parts Discussed in Thread: DSI-TUNER, SN65DSI85

Hello expert,

My customer has questions when using DSI tuner. Please see below picture, right half is enable test pattern result and left half is disable test pattern result.

Q1 : When disabling test pattern, 0x36 Vertical_back_porch , 0x38 H_front_porch  and 0x3A  v_fornt_porch will all be 0. Does it mean we can set these 3 torches to 0 when disabling test pattern? If yes, how can SN65DSI84 know this torch value?

Q2 : When disabling test pattern, 0x24/0x25 are all 0, does it mean SN65DSI84 don't need to know Vertical_display_size when disabling test pattern? If yes, how can SN65DSI84 know Vertical_display_size value?

Q3 : Their Panel is 1920 * 1080 and CHA/CHB will cover half(960*1080) and half(960*1080). But when disabling test pattern, 0x20 and 0x21 are set to 1920. When enabling test pattern, 0x20 and 0x21 are set to 960. We would like to know if it is right.

Q4 : Does TI recommend to enable or disable test pattern?

Q5 : txt. file generated by DSI tuner includes 0x13, 0x22, 0x23, 0x26, 0x27, 0x2a 0x2b, 0x2e, 0x2f, 0x32, 0x33, 0x35, 0x37, 0x39, 0x3b, 0x3d, 0x3e these 17 registers are all 0, but we cannot find these registers in datasheet. Do we have to follow txt. file to fill in SN65DSI84 register or can we skip these registers? 

Thanks a lot for your help!!

Best regards,

Ann Lien

  • Hi Ann,

    1. Please see the register descriptions in the datasheet. Some of these registers are test pattern only registers, so their value does not matter if the test pattern is not used which is why the DSI-Tuner sets them to 0. 

    2. See above. The SN65DSI84 only counts lines to know the vertical display size.

    3. The test pattern is only for CHA with the DSI84, which is why the horizontal settings are doubled to match the display.

    4. Only enable the test pattern if you're using the test pattern.

    5. These registers are for the SN65DSI85. They are not included in the SN65DSI84 so they should all be 0. If these registers are not 0 in the generated txt file then the customer.