DLPC3478: HOST_IRQ signal stays high

I dowloaded "DLP Pico Boot Diagnostic Tool" and run. It outputs:

"DLPC34XX Boot Diagnostics Tool
Single controller detected
Initialize PAD: PASS"

No more message shown. I dont understand which stage failing.

Best regards.

Hi John,

To clarify:

• VOFS & VBIAS go high and stay high?
• VRESET goes low and stays low?

Do you get the same printout from the Boot Diagnostic tool each time? Try taking the DMD out and resetting it in place. Can you also monitor the I2C lines during the boot up of the diagnostic tool? We will want to make sure the I2C line isn't getting stuck. 

Best,

Maximus

Hi Maximus,

Do you mean IIC0 lines? I do not have acces to IIC1 lines.

Yes, I get the same printout from the Boot Diagnostic tool each time, even if no DMD presents. I tried resetting with PROJ_ON signal multiple times but no luck. I have some voltages on VOFS & VBIAS but a few volts. If it should 18V for VBIAS and 10V for VOFF, i am not getting it. Also VRESET around -1V.

Best, 

John.

Hi John, 

Yes, I do mean IIC0. Please also check your Vofs, Vrst, Vbias: do they reach the appropriate values and then fall or are they never reaching the correct values? Vbias should be 18V, Vrst = -14V, Vofs = 10V.

Best,

Maximus

Hi Maximus,

After i checking Vbias, Vreset and Voffset, none of the voltages started generating. IIC lines pulled up to 3.3v and no commination occurs. Here is the output of Diagnostic tool:

Best, 

John.

I just wondering when DMD_EN signal send to DLPA3000? even if no dmd connected to system, is this signal generated? I dont see INT_Z signal to go down, it stays high.

Hi John,

The DMD_EN signal is set as a part of the firmware .img. It seems like either your DLPA3000 is sensing a fault and shutting off or I2C communication is hanging. 

INT_Z should go high and remain high, does RESETZ go high? You say you don't see Vofs, Vrst, Vbias "generate". They never come up during startup or they turn on then turn off? Are you able to communicate with the controller via I2C once the boot diagnostic tool has paused?

Best,

Maximus

Hi Maximus,

I will check the RESETz and INTz signals again ASAP. Are the DLPA3000 SPI pins 3.3V tolerant if VSPI is set to 1.8V? Can I communicate with an external device for debugging purposes? Also, are the SPI lines connected to DLPC3478 3.3V tolerant? Finally, Vofs, Vrst, and Vbias never come up during startup.

Best,

John

Hi Maximus,

I checked RESETz and INTz signals and they are always high. After reinstalling the firmware we have more messages with boot diagnostic tool.

DLPC34XX Boot Diagnostics Tool
Single controller detected
Initialize PAD: PASS
Combination Check
Checking DMD Connection: PASS
Checking Valid Combination: FAIL
Checking PAD outdated: PASS
Checking Fuse ID: FAIL
PMIC: Err - unknown rev?
DMD: .3 Err - unknown fuse id: 0
Controller: DLPC3478
Failed Overall Combination Check

Here is the output of DRST_HS_IND

Best, John

Hello John,

You could connect an external device but if possible we do not recommend connecting the 3.3V directly and instead using a voltage level translator. Could you also provide screenshots of your schematic specifically around the DMD HS/LS interface?

Best,

Maximus

Hi Maximus,

Thanks for the information about 3.3V. Here are the screenshots. In PCB design, under the traces there are ground planes.

bottom layer:

top layer:

schematic:

Best,

John

Hi Maximus,

I use DMD3010LC version similar to evm optical engine design. I removed DMD_LS_RDATA ans shorted the line but no change in Boot Diagnostics Tool output.Is there any other recommendation for debugging the issue?

Best,

John

Hello John,

We are looking into your issue further and we will get back to you early next week. 

Best,

Maxine

Hi John,

Do you have an DLP3010EVM-LC you can connect your optical engine to? If so I would recommend flashing it with the boot diagnostic tool, connecting your optical engine with DMD and reading the printout of the boot diagnostic tool. This way we can narrow the issue between a faulty DMD or your custom board.

Best,

Maximus

Hi Maximus,

I checked the optical engine, and it works with the EVM module. The issue is related to our hardware design. After checking the design, I found a dodgy soldering on the SPI_CS pin. After fixing the soldering, DLPA and DLPC communication (SPI) started working again.

After that, I saw the INTZ pin go low 70 ms after being high. I narrowed down one of the problems to be DLPA related. Then I checked the schematic of my design and found that I did not connect the PWR3 and PWR4 lines (only PWR4_IN with a 1 uF cap connected). I suspected this was triggering the interrupt on the DLPA side. I tried to connect the inputs and outputs with appropriate capacitors. I saw 2.5V on PWR3 and ~12V on the PWR4 output. While observing the INTZ and RESETZ, INTZ stayed high, but RESETZ never went high again. While observing the output of PWR4, I saw smoke on the PWR4 pins. Fortunately, I have a second board. If I can get test firmware to disable (mask) the interrupt for DMD_FAULT, I can make sure that the issues are related to DMD_LDOs

Best,

John

Hi John, 

Glad we could narrow down the issue! Unfortunately we aren't able to disable the interrupt via fw, even if since the controller isn't initializing properly it likely wouldn't be disabled till the controller is up and running.

With the changes you've made are we still not seeing Vofs, Vrst, Vbias? I would recommend making sure the PWR4 connections are correct and nothing is shorted. Feel free to send a screenshot of your DLPA schematic.

Best,

Maximus

Hi John,

I got an email that you replied to this post, though I don't see it now.

It seems like you are getting all the proper signals up until Vbias, Vofs, Vrst, are you able to monitor the SPI lines to the DLPA3000 to determine if there is any communication? Are Vbias, Vofs, Vrst trying to come up and shutting down or just never coming up at all? This could indicate a damaged dmd, I would recommend swapping out the dmd as well.

Best,
Maximus