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TCA9803: hang-up issue

Part Number: TCA9803

Tool/software:

Hi TI

We replaced our DUT’s PCA9617 to TI TCA9803. (Side A 1.8V/ Side B 3.3V)

We followed the spec to NC the side B pull up resistor.

The VOL is better for TCA9803 obviously.

 (see TCA9803_PIC1.png)

But when we open 0x70 mux channel like 1/3/6

When we detect the bus or read device register, the I2C bus will hang-up like below log and measurement.

It's working fine for the 

(see TCA9803_PIC2.png)

root@v3000:~# i2cset -y 2 0x70 0x02

root@v3000:~# i2cdetect -y -r 2

      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f

00:        i2c_designware AMDI0010:03: i2c_dw_handle_tx_abort: lost arbitration

                  -- -- -- -- -- -- -- --

 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

 40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

 50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f

 60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f

 70: 70 71 72 73 74 75 76 77                        

 root@v3000:~# i2cdetect -y -r 2

      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f

00:                         08 09 0a 0b 0c 0d 0e 0f

 10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f

 20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f

 30: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f

 40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f

 50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f

 60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f

 70: 70 71 72 73 74 75 76 77                        

 root@v3000:~#

 

We tried 4 unit and got the same result, so I think it’s not a rework issue.

Below is our I2C tree.

(see I2C_tree.png)

  The PCA9617 which we replaced to TCA9803 is on CPU board U7. (We NC side B pull up resistors: R55/R57 for TCA9803)

(see U7 schematic.pdf)

Can you help to check what might cause this hang-up issue and what we can do for analysis? Thanks.

Rice