DS90UB949-Q1: Accessing the internal EDID (SRAM)

Hi Jack-san,

Thank you for your answer.

I have a follow-up question.

Can I set it using the GUI by entering 1080x960 in the blue box shown below?
If so, what exactly is written to which address?

I'd like to know how to verify that the video signal is being transmitted correctly.
Besides checking the Built-In Self Test (BIST) and the PASS and LOCK terminals on the 948, are there any other methods?
Also, I'd like to check if there's a problem with the connection between the deserializer (DS90UB948-Q1) and the LCD.
Is it correct to assume that using a Pattern Generator will allow me to display the video only between the deserializer and the LCD, regardless of the signal from the serializer?

Best Regards,
Ishiwata

Hi Ishiwata-san,

Shuji Ishiwata said:

Can I set it using the GUI by entering 1080x960 in the blue box shown below?
If so, what exactly is written to which address?

It is possible to set the EDID using the GUI but this will involve writing many registers manually. EDID is a 256 byte configuration file that contains that video timings to be read by the HDMI TX. The EDID register space is accessed through the APB registers. The script I previously sent has a loop that writes all 256 registers in the EDID space.

If you know the complete video timings which include the horizontal and vertical blankings, I can generate an EDID for the 1080*960 timing.

Shuji Ishiwata said:

Besides checking the Built-In Self Test (BIST) and the PASS and LOCK terminals on the 948, are there any other methods?

The below script will readback the active video timing from the 948. This script should only be used for debug purposes and not for runtime diagnostics. Typically this script has to be executed twice to get the horizontal active timing to readback correctly.

UB948 = 0x58
board.WriteI2C(UB948,0x68,0x19) # H active High monitor
Hhigh = board.ReadI2C(UB948, 0x69, 1)
board.WriteI2C(UB948,0x68,0x09) # H active Low monitor
Hlow = board.ReadI2C(UB948, 0x69, 1)
board.WriteI2C(UB948,0x68,0x39) # V active High monitor
Vhigh = board.ReadI2C(UB948, 0x69, 1)
board.WriteI2C(UB948,0x68,0x29) # V active Low monitor
Vlow = board.ReadI2C(UB948, 0x69, 1)
mask = int('00111111',2)
hlowmask = Hlow & mask
hhighmask = Hhigh & mask
vlowmask = Vlow & mask
vhighmask = Vhigh & mask
hhighmask = hhighmask << 6
vhighmask = vhighmask << 6
Hactive = hhighmask | hlowmask
Vactive = vhighmask | vlowmask
print Hactive ,"x", Vactive  #print out detected Dimensions
board.WriteI2C(UB948,0x68,0x0) #Disable readback feature

Shuji Ishiwata said:

Is it correct to assume that using a Pattern Generator will allow me to display the video only between the deserializer and the LCD, regardless of the signal from the serializer?

Yes the 948 pattern generator will allow the video to be sent from the deserializer regardless of the signal from the serializer. The 948 pattern generator is recommended to be enabled via the 948 local I2C bus as remote I2C communication will be disabled when using the internal oscillator of the 948.

Below is an app note that covers the pattern generation feature for FPD3 devices such as the UB949 and UB948. 948 pattern generation can be enabled with the dedicated tab in the 948 ALP profile.

https://www.ti.com/lit/an/snla132g/snla132g.pdf?ts=1781123402537&ref_url=https%253A%252F%252Fwww.google.com%252F

Best,

Jack