The Software Reset call is a command send from the controller on the I²C bus that instructs all devices that support the command to be reset to power-up values. In order for it to function as expected, the I²C bus must be functional and no devices can be hanging the bus.

The Software Reset Call is defined as the following steps:

1. A START condition is sent by the I²C bus controller.
2. The address used is the reserved General Call I²C bus address '0000 000' with the R/W bit set to 0. The byte sent is 0x00.
3. Any devices supporting the General Call functionality will ACK. If the R/W bit is set to 1 (read), the device will NACK.
4. Once the General Call address is acknowledged, the controller sends only 1 byte of data equal to 0x06. If the data byte is any other value, the device will NOT acknowledge or reset. If more than 1 byte is sent, no more bytes will be acknlowedged, and the device will ignore this I2C message, considering it invalid.
5. After the 1 byte of data (0x06) is sent, the controller sends a STOP condition to end the Software Reset sequence. A repeated START condition will be ignored by the device, and no reset is performed.

Once the above steps are completed successfully, the device will perform a reset. This will clear all register values back to power-on defaults. All P-ports will be configured as inputs, regardless of the port mode configuration of the P3 port.