DLP6500FLQ: Internal Memory Test Failed!

Hello Shijiang,

Let me answer your second question first. The DMD does not have any memory other than the currently displayed (or next to be displayed) pixel data [and a 1 row buffer]. Also, it cannot be queried, so the error cannot be originating there.

The memory being referred to is the DDR memory attached to the controller (DLPC900). This likely means that there is a problem with the connections (bad solder joint or other) to one of the DDR memory chips.

I am a little bit confused. because it sounds like you are having an issue in Pattern on-the-fly Mode which does not use parallel flash, but loads patterns directly into DDR memory over USB.

For "Pre-stored Patterns, you have to build a custom firmware and load the firmware to parallel flash. If there were a serious problem with parallel flash I would not expect the unit to boot. But if there were a problem with DDR memory you would experience issues with both Pattern modes, since the both load pattern data to DDR memory. One over USB and the other from parallel flash.

Did you use the same DDR memory component as the EVM?

Fizix

Hello Fizix, Thanks for your reply.

We use three chips of parallel flash same as EVM,I think all flash work well,because update and boot firmware all OK.

We use "Pattern On-The-Fly mode" only for test by USB,because no images are displayed on DMD in "Pre-stored pattern mode"(pre-stored pattern) and " Video mode"(test pattern)

In our system ,no DDR memory be used! and the EVM also didnot! Which chips are DDR memory in 6500EVM?

I think that  it should be the intenal memory of DLPC900, but I donot konw how to debug it! 

Please give me  more suggestion for this issue.

Thank you very much!

Thanks Fizix!

I have sloved the issue! 1.8V for the internal DRAM of DLPC900 is bad!(only 0.8V!).

Now "Internal Memory Test Passed" is checked!, But also no images are displayed on DMD! When power up,the operation mode of the GUI allways is "pre-stored pattern mode".

If we change it  to other   mode(i.e. "Pattern On-The-Fly  mode"),the LED(D6) will stop blink,and GUI also stop!

If we clear all existing pattrern images and batche files, update the firmware,the initial status of GUI is "Video mode",We can change it to "pattern on-the-fly",then load test.txt file and update LUT,but aslo no images are displayed on the DMD!

The DMD(DLP6500FLQ) is OK! because if  we change it to other 6500 EVM,it work well.

Why is this issue?

 

 

 

Hello Shijiang,

Do you have a video input? And if so can you switch to video mode and see the incoming video?

Hello Fizix,

No video input! but we can try to simulate it by FPGA.

By the way,

1.In video mode(use no pre-stored pattern firmware),we select the source of "Internal Test Pattern",also no images be displayed on DMD!

2.All powers(3.3v,8.5v.16v,-10V) of  the DMD are work well.

 How to debug this issue?

Which signals between DLPC900 and DLP6500 are important to focus on.

Thanks!

Hello Fizix,

I just took a long time holiday.

According to your advice, I  took a scope capture of the SCTRLs ,   D_CLKs and all Data(DDA and DDB)  LVDS  lines  to DLP6500 in the " Internal Test Pattern"  of  Video Mode,  But I don't see any activity(pulse level), and all signals are DC level( all xxx_P=1.0V, all xxx_N=1.3V).

Why? please tell me the pulse types of these signals

Hello Shijiang,

If you have no D_CLKS, there is something very wrong. Make sure your scope is fast enough to see the 400 MHz D_CLK. It seems to recognize the part (from your GUI screenshot), but is not sending data/clocks.

Do you have one of our EVMS to test the same operations on?

Fizix

Hello Fizix,

1. After start GUI, no any signals of D_CLKS, SCTRLS and all Data LVDS are captured. But the voltages of VOFFSET(+8.5V), VRESET(-10V) and VBIAS(+16V) all are right! the PG signal of TPS65145 is ok(3.3V). No image be displayed on the DMD.

2.When we set the test pattern, we can capture the signals of D_CLKS, SCTRLS and all Data LVDS, But the voltages of VOFFSET(+8.5V), VRESET(-10V) and VBIAS(+16V) all are lose! the PG signal of TPS65145 is not good(0V). also no image be displayed on the DMD, and the DMD is wery hot after it works for a while!

We have a EVM with DLPC4422+DLP6500, but we can not find any test points of D_CLKS , SCTRLs , etc.

Thanks for your reply!