4 I/O Interfaces
The I2C interface uses the SDA and SCL pins to transfer commands/data/status to and from the SHA104-TFLXAUTH device. The SWI transfers data using a single pin. Data flow is controlled by the host controller for both interfaces. Power is provided to the device through the SI/O signal when used in a parasitic power application.
Interface Terminology
- Host:
- The host MCU generates the command and controls the data flow on the bus to one or more client devices.
- Client:
- The SHA104-TFLXAUTH device always operates as a client device on the bus and cannot take control of the bus.
- Device Address:
- 7-bit address used to address a client device. This is part of the first byte sent to a client device for each write or read transaction.
- Open-Drain:
- The SHA104-TFLXAUTH device has an open-drain output buffer where the bus is actively pulled low by the output buffer when data are read from the device but are passively pulled high by an external pull-up resistor.
Remember: The I2C
standard uses the terminology “Master” and
“Slave”. The equivalent Microchip terminology used
in this document is “Host” and “Client”,
respectively. This terminology was also adopted
for the SWI.