Christopher Ruehl

hi @jock
 
I agree that changing the SMD 0201 parts is a real challenge - for this reason I used 0402's soldered them direct to the level shifter and run a tiny wire to the 5V source.
I'm thinking that an SoC side strong pull-up would do the trick eventually and remove R90611/12 entirely. But I haven't test this - but will do that with the next PCB I get on my table.
 
The Level-shifter is a Texas Instruments TX0102DCU with and with OE is high the internal 10K pull ups are enabled.  That might me not enough for the external monitor so the 6.8k has been applied.
Same for the SoC side, 10K only , so I support the internal SDA/SCL lines with the light diving strength of 2ma.
Datasheet:
8.3.5 Pullup or Pulldown Resistors on I/O Lines Each A-port I/O has an internal 10-kΩ pullup resistor to VCCA, and each B-port I/O has an internal 10-kΩ pullup resistor to VCCB. If a smaller value of pullup resistor is required, an external resistor must be added from the I/O to VCCA or VCCB (in parallel with the internal 10-kΩ resistors). Adding lower value pull-up resistors will effect VOL levels, however. The internal pull-ups of the TXS0102 are disabled when the OE pin is low.  
I would say it doesn't hurt to add the changes to the DTS for the i2c7_xfer pinctrl. But without fixing the Pull-up value on the 5V it will not improve anything.
 
Yes it is tiny tiny.

hi @jock
 
I agree that changing the SMD 0201 parts is a real challenge - for this reason I used 0402's soldered them direct to the level shifter and run a tiny wire to the 5V source.
I'm thinking that an SoC side strong pull-up would do the trick eventually and remove R90611/12 entirely. But I haven't test this - but will do that with the next PCB I get on my table.
 
The Level-shifter is a Texas Instruments TX0102DCU with and with OE is high the internal 10K pull ups are enabled.  That might me not enough for the external monitor so the 6.8k has been applied.
Same for the SoC side, 10K only , so I support the internal SDA/SCL lines with the light diving strength of 2ma.
Datasheet:
8.3.5 Pullup or Pulldown Resistors on I/O Lines Each A-port I/O has an internal 10-kΩ pullup resistor to VCCA, and each B-port I/O has an internal 10-kΩ pullup resistor to VCCB. If a smaller value of pullup resistor is required, an external resistor must be added from the I/O to VCCA or VCCB (in parallel with the internal 10-kΩ resistors). Adding lower value pull-up resistors will effect VOL levels, however. The internal pull-ups of the TXS0102 are disabled when the OE pin is low.  
I would say it doesn't hurt to add the changes to the DTS for the i2c7_xfer pinctrl. But without fixing the Pull-up value on the 5V it will not improve anything.
 
Yes it is tiny tiny.

hi @jock
 
I agree that changing the SMD 0201 parts is a real challenge - for this reason I used 0402's soldered them direct to the level shifter and run a tiny wire to the 5V source.
I'm thinking that an SoC side strong pull-up would do the trick eventually and remove R90611/12 entirely. But I haven't test this - but will do that with the next PCB I get on my table.
 
The Level-shifter is a Texas Instruments TX0102DCU with and with OE is high the internal 10K pull ups are enabled.  That might me not enough for the external monitor so the 6.8k has been applied.
Same for the SoC side, 10K only , so I support the internal SDA/SCL lines with the light diving strength of 2ma.
Datasheet:
8.3.5 Pullup or Pulldown Resistors on I/O Lines Each A-port I/O has an internal 10-kΩ pullup resistor to VCCA, and each B-port I/O has an internal 10-kΩ pullup resistor to VCCB. If a smaller value of pullup resistor is required, an external resistor must be added from the I/O to VCCA or VCCB (in parallel with the internal 10-kΩ resistors). Adding lower value pull-up resistors will effect VOL levels, however. The internal pull-ups of the TXS0102 are disabled when the OE pin is low.  
I would say it doesn't hurt to add the changes to the DTS for the i2c7_xfer pinctrl. But without fixing the Pull-up value on the 5V it will not improve anything.
 
Yes it is tiny tiny.