MCP23008 IO Expander - Detecting 2 I2C devices

Now I did the following test.

1.  Connected the I2C cable, with only 3 wires (Gnd, SCL1, SDA1) daisy chained from the level shifter board to the MCP23008 board.

2.  Connected a new PSU with 5V0, 3V3 to the MCP23008 board.  In other words, the RPi (with GPIO signal routing board, 5 channel 3V3/5V0 level shifter board, MCP23017 board) is using a 5.25V PSU.

3.  The MCP23008 board is connected to a second 3V3/5V0 PSU.

4. Then I booted RPi and used the i2cdetect command to detect the 2 devices MCP23017, and MCP23008.

5. I found that i2cdetect could detect the 2 devices at address 0x20 and 0x22.  Then I set the MCP23008's address pins A2A1A0 from 000 to 100.  Then i2cdetect detected 0x22 and 0x24.

Everything went smoothly.

So far so good.  Time I went jogging.

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