Linux/am5728: LVDS issue

tracemhos

Part Number: AM5728
Other Parts Discussed in Thread: AM5728, DS90C387

Tool/software: Linux

I'm using the AM5728 coupled with the DS90C387 in a single-to-dual LVDS setup, however we cannot get anything to show up on the display (not even a scrambled image). Our display clock frequency is 74MHz, we have properly configured the RGB clock frequency to 148MHz (DS90C387 splits this clock). It appears that the hsync, vsync, and DE has a period 1/2 as long as its supposed to be - wondering how to adjust the timing parameters of these signals?

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Try setting the RGB clock frequency to 74MHz.

0 tracemhos over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

If I do that, the DS90C387 will divide the clock down to 37MHz, which is too low. I need to maintain a 148MHz RGB frequency while independently changing the Hsync and Vsync timing

0 Biser Gatchev-XID over 8 years ago in reply to tracemhos

TI__Guru**** 393215 points

What software are you using?

0 tracemhos over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

We are using Linux, I don't know what Kernel version though. We have an outside software company working on the software build, will eventually use Android.

0 Biser Gatchev-XID over 8 years ago in reply to tracemhos

TI__Guru**** 393215 points

Well, then you have to contact them. Display parameters are configured in the Device Tree, and possibly they got the timings wrong (used the 148MHz pixel clock to calculate them).

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Linux/am5728: LVDS issue