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DS90UB949-Q1: Display side touch event lost after errata changing

Part Number: DS90UB949-Q1
Other Parts Discussed in Thread: DS90UH949-Q1

Tool/software:

Hi Team,

We have updated the UB949 scripts based on the errata file. Which is referring the DS90UH949-Q1 Init Code Example Rev 1p1.txt

# Errata #7

    board.WriteI2C(UB949,0x16,0x02) # Adjust BCC watchdog timer to minimum

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############################
# DS90UH949-Q1 Init Code Example v1.0
# 949->948, Dual FPD-Link STP, 1920x1080@60Hz
############################

import time
import sys

# System dependant variables - adjust according to system 
UB949 = 0x18        # 949 I2C Address
UB948 = 0x68        # Remote 948 Address

def pollstate():
    count=0
    board.WriteI2C(UB949,0x23,0x80)
    board.WriteI2C(UB949,0x24,0x80)
    mask = int('11111',2)
    state = board.ReadI2C(UB949,0x24,1)
    while (state & mask) != 27:   #27 = 5'b11011
        time.sleep(0.01)  #10ms delay
        state = board.ReadI2C(UB949,0x24,1)
        count = count +1
        if count == 10:
            print "Error: Serializer is not in Normal state"
            return(1)
    
    board.WriteI2C(UB949,0x23,0x0)
    board.WriteI2C(UB949,0x24,0x0)

        

def initsequence():

    board.WriteI2C(UB949,0x03,0xDA) # Set I2C passthrough
    
    linked = 0
    retry = 0
    mask = int('10000000',2)
    while linked == 0:
        STS = board.ReadI2C(UB949,0x5A,1)
        if ((STS & mask) != 0):
            linked = 1
            print "Deserializer Detected"
        else:
            time.sleep(0.1)
            retry = retry + 1
            if retry == 10:
                print "Error: No Deserializer Detected"
                return()

    board.WriteI2C(UB948,0x4A,0x01) # Disable OLDI outputs on 948 to prevent screen glitches from appearing during the init process 

    ##### Init A Sequence

    # Errata #2, 3, 4
    board.WriteI2C(UB949,0x5B,0x03) # Force dual FPD-Link, disable reset on PLL frequency change 

    # Errata #7
    board.WriteI2C(UB949,0x16,0x02) # Adjust BCC watchdog timer to minimum

    state_error = pollstate()  # Poll 949 state machine prior to applying init B errata

    if state_error == 1:
        return()

    ##### Init B Sequence
    # Add VCO optimization script here for script #3

    # Reset HDMI PLL after TMDS clock has stabilized 
    board.WriteI2C(UB949,0x40,0x10)
    board.WriteI2C(UB949,0x41,0x49)
    board.WriteI2C(UB949,0x42,0x10)
    board.WriteI2C(UB949,0x42,0x00)

    # Reset FPD PLL 
    board.WriteI2C(UB949,0x40,0x14)
    board.WriteI2C(UB949,0x41,0x49)
    board.WriteI2C(UB949,0x42,0x10)
    board.WriteI2C(UB949,0x42,0x00)

    board.WriteI2C(UB948,0x01,0x01) # Digital reset to restart AEQ 
    time.sleep(0.1) # Allow time for 948 to relock 
    board.WriteI2C(UB948,0x4A,0x00) # Enable OLDI outputs on 948

initsequence()

After the changes, there are some of the paired display unit lost the touch function, the interrupt should be passed back to SoC was lost.

It looks like the issue is relate to the “writeByte(fd, gSlaveAddress[screen][SA_BOARD], 0x16, 0x02);”, after change the 0x02 into 0x10, the issue can be removed.

Why the bi-directional watchdog initial value should e configure as minimum? Based on the current touch interrupt lost issue, what value is suggested to configure to the watchdog?

Thanks!

Best,

Frank

  • Hi Frank,

    Who is the tier 1 and OEM?

    After the changes, there are some of the paired display unit lost the touch function, the interrupt should be passed back to SoC was lost.

    Could you share information on how many systems this is occurring on? In addition, on systems that do witness this loss of interrupt communication, does it occur on every power cycle? Or only sometimes?

    Why the bi-directional watchdog initial value should e configure as minimum?

    In rare instances, FPD-Link III back-channel data errors caused by system fault conditions (i.e. abrupt power down of remote DES, cable disconnects) may result in the 949 sending inadvertent I2C transactions on the local I2C bus prior to determining loss of valid back channel signal. Setting this minimum value minimizes the duration of inadvertent I2C events.

    Best,

    Nikolas

  • Hello Nikolas,

    Could you share information on how many systems this is occurring on? In addition, on systems that do witness this loss of interrupt communication, does it occur on every power cycle? Or only sometimes?

    Only one paired display unit has this problem by now, when finger slip quickly on this screen; 

    I2C read events 6000 times, and failed 180 times during that period;

    touch event logs:

    Line 44414: [SLOG]2024-5-17 02:04:15.796-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 1693, y: 317
    Line 44415: [SLOG]2024-5-17 02:04:15.809-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 1693, y: 318
    Line 44416: [SLOG]2024-5-17 02:04:15.839-E:mtouch-aptiv-ts[ERROR]: aptiv_ts_i2c_read_reg: devctl failed No error for 0 times
    Line 44425: [SLOG]2024-5-17 02:04:15.894-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 0, y: 0
    Line 44432: [SLOG]2024-5-17 02:04:15.954-E:mtouch-aptiv-ts[ERROR]: aptiv_ts_i2c_read_reg: devctl failed No error for 0 times
    Line 44456: [SLOG]2024-5-17 02:04:16.169-E:mtouch-aptiv-ts[ERROR]: aptiv_ts_i2c_read_reg: devctl failed No error for 0 times
    Line 44491: [SLOG]2024-5-17 02:04:16.770-E:mtouch-aptiv-ts[ERROR]: aptiv_ts_i2c_read_reg: devctl failed No error for 0 times
    Line 44492: [SLOG]2024-5-17 02:04:16.826-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 1630, y: 456
    Line 44497: [SLOG]2024-5-17 02:04:16.946-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 1645, y: 453
    Line 44521: [SLOG]2024-5-17 02:04:17.227-I:mtouch-aptiv-ts[INFO]: get_coords: Index [0], x: 1557, y: 454

  • Hello,

    It seems like this may be a symptom of a different, currently undiagnosed issue, and increasing the watchdog timer is effectively masking an issue that may be occurring on the I2C bus.

    To help better identify the next steps, could you please provide me with a schematic of the 949 for review?

    Best,

    Nikolas

  • 949.pdf

    Hello,

    Please review this schematic of 949, thanks.

  • Hello,

    One thing of note on the schematic is that R365 and R366 have values of 1.8kOhm, but the datasheet recommends using pull-up resistors of 4.7kOhm. Some additional follow-up questions:

    • How many total systems have been tested?
    • Are you able to probe the I2C_SCL and I2C_SDA pins and provide a capture during the abnormal state?
    • Could you please do an ABA swap on the system and see if the issue persists (i.e. swap out the 949 IC on the system for a different 949 IC)?

    Best,

    Nikolas