Hi,
Recently I am testing a board which have 12 INA226 and 4 DAC7678, and something wired have happened.
Here is the I2C slave address of my board:
Device |
RefD. |
Address |
Notes |
PCA9539 |
U53 |
0x74 |
I/O expander |
SC18IS602B |
U38 |
0x28 |
I2C TO SPI |
DAC7678-1 |
U23 |
0x4C |
VOL A1~A8 |
DAC7678-2 |
U35 |
0x4D |
PWR A1~A6 CTR |
DAC7678-3 |
U25 |
0x4E |
VOL B1~B8 |
DAC7678-4 |
U24 |
0x4F |
PWR B1~B6 CTR |
INA226-1 |
U28 |
0X40 |
PWR_A1 MON |
INA226-2 |
U16 |
0X41 |
PWR_A2 MON |
INA226-3 |
U15 |
0X42 |
PWR_A3 MON |
INA226-4 |
U18 |
0X43 |
PWR_A4 MON |
INA226-5 |
U17 |
0X44 |
PWR_A5 MON |
INA226-6 |
U20 |
0X45 |
PWR_A6 MON |
INA226-7 |
U29 |
0X46 |
PWR_B1 MON |
INA226-8 |
U19 |
0X47 |
PWR_B2 MON |
INA226-9 |
U22 |
0X48 |
PWR_B3 MON |
INA226-10 |
U21 |
0X49 |
PWR_B4 MON |
INA226-11 |
U37 |
0X4A |
PWR_B5 MON |
INA226-12 |
U36 |
0X4B |
PWR_B6 MON |
Table 1: I2C Slave Address assignment
When we perform the I2C test, all other devices work well but the INA226 located at 0x47, and we have probe the SCL and SDA signal with a scope when trying to read registers from the 0x47 INA226.
Figure 1 is the screenshot of the waveform, we can only read back 0x00 from the INA226 at 0x47, and the other 11 INA226 work very good.
Figure 1: Waveform when performing read action to the INA226 at 0x47
Then we have doing some test:
1. Only solder these 12 INA226 to the board, all of them work good, include the INA226 at 0x47. We can read back 0x4127 from register 0x0;
2. Then solder one DAC7678 (U35) to the board, the I2C address of the DAC is 0x4D; Then all the data readout from the INA226 at 0x47 is 0x00 !;
All other 11 INA226 and the DAC7678 at 0x4D work good.
3. Remove the DAC7678 at 0x4D, then solder the DAC7678 at 0x4E (U25), the problem still are there. We can not read back anything from the INA226 at 0x47.
All other 11 INA226 and the DAC7678 at 0x4E work good.
4. Remove the DAC7678 at 0x4D, then there are only 12 INA226 in the board. We performing the reading scan again, all of them work well now, include the INA226 at 0x47.
So we suspect there are some conflicts when we use DAC7678 and INA226 at the same time.
Can anyone from TI can verify that for us?
Thank you very much!