I2CRECV Pin, ByteVar, AckVal

Function
Receives ByteVar from the I2C bus defined by Pin.

• Pin defines the SDA pin of the I2C bus. Pin may any I/O pin except RA.3 (RA.7 on the SX52), RB.7, RC.7, RD.6, or RE.6 (see below).
• ByteVar  is a byte variable that will hold the value returned by the slave device.
• AckVal  is a bit-value that will be sent to the slave after ByteVar has been received (Ack = 0, Nak = 1).

Quick Facts

	SX18/20	SX28	SX48	SX52
SDA pin	RA.0 .. RA.2 RB.0 .. RB.6	RA.0 .. RA.2 RB.0 .. RB.6 RC.0 .. RC.6	RA.0 .. RA.2 RB.0 .. RB.6 RC.0 .. RC.6 RD.0 .. RD.6 RE.0 .. RE.6	RA.0 .. RA.6 RB.0 .. RB.6 RC.0 .. RC.6 RD.0 .. RD.6 RE.0 .. RE.6
SCL pin	Next pin in same group as SDA assignment.
Transmission rate	Approximately 50 kBits/sec.
Special Notes	Both the SDA and SCL pins must have 4.7 kΩ pull-up resisters.

Explanation
The I2C protocol is a form of synchronous serial communication developed by Philips Semiconductor. It only requires two IO pins and both pins can be shared between multiple I2C devices. The I2CRECV instruction reads an eight-bit value from a previously addressed device on the I2C bus (SDA and SCL pins).

Note that the SCL pin is automatically assigned to the next higher pin in the same group as the SDA pin, so the SDA pin may not be assigned to RA.3 (RA.7 on the SX52), RB.7, RC.7, RD.7, or RE.7.

Related instructions: I2CSEND, I2CSTART, and I2CSTOP