Part Number: DS90UB948-Q1
Hello,
Our customer designed a SERDES circuit using DS90UB983+DS90UB948. When the host pauses playback for a long time (about 12 hours), a black screen fault will occur. At this time, the backlight of the monitor is normal, and the register value of DS90UB948 is the same as when it is displayed normally. After resetting DS90UB948, the display screen can show normally. Can you help me analyze it?
Thank you for your support. Let me add the register values of the 947 and 948 when the issue occurs.
1. When the screen cable length is changed from 1.5 meters to 10 meters, the value of the 948 register 0x3B remains 0x0F. It is uncertain whether this value is correct.
2. These are the register values under normal conditions.
Hi Fushen,
Yeah I'm not sure this makes sense actually. AEQ will adapt differently based on cable length.
If I want to put this on my bench and try few things to see if I can reproduce can you explain to me how this failure manifest?
We need a scope shot showing all rails with respect to each other as well as time measurements similar to datasheet plot.
I'm suspecting a simple sequencing issue when you need to apply a soft reset to the 948 (0x1 = 0x1) as mentioned in the datasheet
Regards,
Fadi A.
Hi Fadi，
Thank you for your support. The feedback is as follows:
1、We use 947 and 948
2、The comparison between the register values before and after the fault is shown in the following figure:
3、We used a logic analyzer to measure the timing of 947 and 948 ourselves, and the timing is shown in the following figure:
4、Use an oscilloscope to capture the timing sequence of side 947 as shown in the following figure:
5、We encountered this issue on over 10 machines, and the testing steps were as follows: the system was running continuously without any human operation, and there was a probability of encountering this gray screen problem after running for about 24 hours.
Hi Fushen,
For power sequence to be captured correctly we need both Ser and Des side capture and need to zoom into the ramp time of the supply to ensure it matches datasheet recommendation. We need power sequence capture of the 947 and 948 please.
I noticed from your dump that you don't have the 947 Erratas applied. This could be a known rare issue called AV mute that you're encountering here.
Here is an example Errata code for 947 - 948 please make sure to apply into your software.
The issue that might be happening here is related to Errata#11
# Errata #11
board.WriteI2C(UB947,0x04,0x90) # Prevent AVMUTE for non-HDCP systems
"""
TI Confidential - NDA Restrictions
Copyright 2020 Texas Instruments Incorporated. All rights reserved.
IMPORTANT: Your use of this Software is limited to those specific rights
granted under the terms of a software license agreement between the user who
downloaded the software, his/her employer (which must be your employer) and
Texas Instruments Incorporated (the "License"). You may not use this Software
unless you agree to abide by the terms of the License. The License limits your
use, and you acknowledge, that the Software may not be modified, copied or
distributed unless embedded on a Texas Instruments microcontroller which is
integrated into your product. Other than for the foregoing purpose, you may
not use, reproduce, copy, prepare derivative works of, modify, distribute,
perform, display or sell this Software and/or its documentation for any
purpose.
YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION ARE
PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,
INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, TITLE,
NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL TEXAS
INSTRUMENTS OR ITS LICENSORS BE LIABLE OR OBLIGATED UNDER CONTRACT,
NEGLIGENCE, STRICT LIABILITY, CONTRIBUTION, BREACH OF WARRANTY, OR OTHER LEGAL
EQUITABLE THEORY ANY DIRECT OR INDIRECT DAMAGES OR EXPENSES INCLUDING BUT NOT
LIMITED TO ANY INCIDENTAL, SPECIAL, INDIRECT, PUNITIVE OR CONSEQUENTIAL
DAMAGES, LOST PROFITS OR LOST DATA, COST OF PROCUREMENT OF SUBSTITUTE GOODS,
TECHNOLOGY, SERVICES, OR ANY CLAIMS BY THIRD PARTIES (INCLUDING BUT NOT
LIMITED TO ANY DEFENSE THEREOF), OR OTHER SIMILAR COSTS.
Should you have any questions regarding your right to use this Software,
contact Texas Instruments Incorporated at www.TI.com.
"""
############################
# DS90UB947-Q1 Init Code Example v1.1
# 947->948, Dual FPD-Link STP, 1920x1080@60Hz
############################
import time
import sys
# System dependant variables - adjust according to system
UB947 = 0x18 # 947 I2C Address
UB948 = 0x68 # Remote 948 Address
StartAmbTemp = 25 # Example temperature measured by local sensor on PCB (Ambient temp around 947). In real system this should be read back from temp sensor during initialization
Hres = 1920 # Expected horizontal active resolution
Vres = 1080 # Expected vertical active resolution
def pollstate():
count=0
board.WriteI2C(UB947,0x23,0x80)
board.WriteI2C(UB947,0x24,0x80)
mask = int('11111',2)
state = board.ReadI2C(UB947,0x24,1)
while (state & mask) != 27: #27 = 5'b11011
time.sleep(0.01) #10ms delay
state = board.ReadI2C(UB947,0x24,1)
count = count +1
if count == 10:
print "Error: Serializer is not in Normal state"
return(1)
board.WriteI2C(UB947,0x23,0x0)
board.WriteI2C(UB947,0x24,0x0)
def initsequence():
board.WriteI2C(UB947,0x03,0xDA) # Set I2C passthrough
linked = 0
retry = 0
mask = int('10000000',2)
while linked == 0:
STS = board.ReadI2C(UB947,0x5A,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 #5 and 6
board.WriteI2C(UB947,0x5B,0x03) # Force dual FPD-Link, disable reset on PLL frequency change
# Errata #10
board.WriteI2C(UB947,0x16,0x02) # Adjust BCC watchdog timer to minimum
# Errata #11
board.WriteI2C(UB947,0x04,0x90) # Prevent AVMUTE for non-HDCP systems
state_error = pollstate() # Poll 947 state machine prior to applying init B errata
if state_error == 1:
return()
# Errata #3
board.WriteI2C(UB947,0x40,0x10)
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x16)
board.WriteI2C(UB947,0x41,0x47)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0xA0)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0x00)
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x00)
time.sleep(0.01)
##### Timing Confirmation
retry = 0
Hconfirm = 0
Vconfirm = 0
while (retry < 3):
board.WriteI2C(UB948,0x68,0x08) # Enable PATGEN BIST
time.sleep(0.1) # Critical time delay - do not adjust to a shorter value
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)
board.WriteI2C(UB948,0x68,0x00) # Disable PATGEN BIST
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
if Hactive != Hres:
retry = retry + 1
board.WriteI2C(UB947,0x40,0x10) # Reset OLDI PLL
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x16)
board.WriteI2C(UB947,0x41,0x47)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0xA0)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0x00)
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x00)
time.sleep(0.1)
else:
Hconfirm = 1
if Vactive != Vres:
retry = retry + 1
board.WriteI2C(UB947,0x40,0x10) # Reset OLDI PLL
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x16)
board.WriteI2C(UB947,0x41,0x47)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0xA0)
board.WriteI2C(UB947,0x42,0x20)
board.WriteI2C(UB947,0x42,0x00)
board.WriteI2C(UB947,0x41,0x49)
board.WriteI2C(UB947,0x42,0x00)
time.sleep(0.1)
else:
Vconfirm = 1
if (Hconfirm == 1) and (Vconfirm == 1):
break
if (retry > 2):
print "Error: Timing confirmation failed. Double check expected video resolution and OLDI video input"
return()
else:
print "Initialization Complete"
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()
- Fadi A.
Hi Fadi，
1、The power on timing of 947 and 948 you pointed out is as follows:
2、In response to the suspicion you mentioned, I will modify the software for testing, and the test results will be replied to within 24-48 hours.