DLP5530Q1EVM: I2C Communication from Custom Host Controller

Another point is that the FPGA pins are configured for 3.3V LVCMOS, i'll see if changing to 3.3V LVTTL makes a difference.

Hi Jonathan -

I am working to find an answer and will get back to you ASAP.

Regards,

Ross

I've attached the waveforms that my controller is sending to the DLP. 

1. Signals are somewhat noisy. I'm not sure how sensative the DLP is to this. I've tested with various devices with I2C and don't see any issues there.

2. I2C was configured as Diagnostic port. SPI was Host. LED is projecting so I believe that means it's in Display mode.

3. I'm sending to address 36h, WR is set to 0, a Read Pre-fetch command (0x01) on the I2C line.

And I'm not seeing an acknowledge from the DLP. Even on the the first byte of data. The full sequence shown in my data logger is attached also

Additionally, I also configured the DLP I2C as Host and sent the following command to dim the projection. This command scheme comes from the SPI interface. I used the same sequence from that to send on the I2C.

Addr|Cmd|Tag|Len|dataLsb|dataMb|Crc

0x36 0x50 0xBC 0x02 0xE9 0x03 0x92

->This sets the dimming level to 1001.

Are you able to communicate with the DLPC230 using the Cheetah USB-SPI adapter connected to the DLPC230 Control Program Lite GUI tool?

Yes, full communication works fine there. 

Also, I just noticed in the DLPC230 Control Program Lite GUI the I2C address can be set to 34h or 36h.

Setting address to 34h or 36h doesn't work.

Have you confirmed the proper setting of each of the TESTPT and other Configuration pins of the DLPC230? For most of them, there are switches on the board. Refer to page 9 of the DLP5530Q1EVM schematic PDF (document number DLP033B):

Yeah, I have the schematic. I set the HOST_IF_SEL to 1 for I2C Host. And to 0 for SPI Host. When set to 1, I can't connect to the SPI Host which is expected.

I'm not sure where the TESTPT's you mentioned are located on the PCB. For the switches they are all 0 except for the HOST_IF_SEL switch.

I tried probing TP10 on the PCB which connects to TSTPT2=I2C-ADDR-SEL and that seems to be set Low. So address is correct at 36h

Did this Dimming Level write command execute properly?

Yes to when the SPI is Host and using the GUI+USB-SPI.

No to when the I2C is Host using the Controller. No acknowledge and the projection stays the same level.

I can also use the USB-SPI to get diagnostic data from the DLP when I2C Host.

Is there maybe status signal to show what the communication error could be? I'm able to get diagnostic data from the SPI.

Also, wanted to point out that the timing seems to be correct too. The measured clock rate is around 100KHz. The signals look clean enough so the DLP controller wouldn't have issue decodeing it I would think.

Frequency = 1/Period = 1/(10usec) = 100KHz

There may be an issue with the address byte....

The DLPC230 I2C address is defined assuming the 8 bits which includes the LSB R/W bit.  It looks like you may have assumed the address we specify is just the 7 bits without the R/W bit.  The 8-bit address is 0x36 and the 7-bit equivalent would be 0x1B.

I'm working from home right now so I'll test this later today but that definetly could be the issue for sure. I'll follow up to confirm.

That didn't seem to work. I still get NACK and dimming level stays the same. I've tried in both SPI/I2C host and no response on the address byte.

What do you think should be the next steps?

Would it be possible to get a test build from you that sends a command on the I2C line to confirm that the port is working on my side? Or maybe can you recommend a USB-I2C cable that works with the DLPC230 GUI tool? I could probe a working bus to compare waveforms.

I'm following up with this. Also, can you confirm that if I hooked up an I2C scanner that I would be able to see the DLP respond back?

Yes, that's correct. I am checking on your other questions and hope to get back to you today.

No problem. I'll double check the wiring and connections to make sure the signal path is good in the meantime.

Also, I hooked up the I2C scanner (Bus Pirate) and was able to detect a sensor that I had connected. However, I don't see anything from the DLP controller.