PIC I2C PPS configuration

0
votes

I will be communicating with some device via SMBus. I use PIC18F26K83 and I will use RB1 and RB2 pins as SCL and SDA pins. My question is about PPS mapping. In datasheet it says that I need to set both of these pins to both input and output. As PPS output selection it is simple because " RxyPPS: PIN Rxy OUTPUT SOURCE SELECTION REGISTER" let's me choose pin,port and SDA/SCL. However, "xxxPPS: PERIPHERAL xxx INPUT SELECTION" register only lets me to choose port and pin. To be more clear let me give an example:

RB1PPS= 0b00001001; //RB1 input PPS

This line only lets me to choose port and pin. It says RB1 is input that is all. On the other hand:

RB1PPS= 0b00100011; // RB1= I2C2 (SCL) output.

This line lets me choose port, pin and also SCL output. It says RB1 is output but also it is SCL.

In datasheet Page: 266 PPS Input register details, there are some register values that I need to use in order to choose input as SDA or SCL. ( I added datasheet)

So my question is: Do I need to choose SDA or SCL for input just like I choose for output? Which code block seems more accurate?

1)

RB1PPS= 0b00001001; //RB1 input PPS
RB2PPS= 0b00001010; //RB2 input PPS
RB1PPS= 0b00100011; // RB1= I2C2 (SCL) output.
RB2PPS= 0b00100100; //RB2= I2C(SDA) output.
I2C2SCLPPS = 0b00001001; // RB1 I2C2 Clock
I2C2SDAPPS= 0b00001010;  // RB2 I2C2 Data

or

2)

RB1PPS= 0b00001001; //RB1 input PPS
RB2PPS= 0b00001010; //RB2 input PPS
RB1PPS= 0b00100011; // RB1= I2C2 (SCL) output.
RB2PPS= 0b00100100; //RB2= I2C(SDA) output

Datasheet: Datasheet of PIC18F26K83

1
pici2csmbus

1 Answers

1
votes

TRY THIS

/* Unlock PPS */

PPSLOCK = 0x55;
PPSLOCK = 0xAA;
PPSLOCKbits.PPSLOCKED = 0x00;


/* Setting of PPS */

/* RB1 <-> SCL2 */
RB1PPSbits.RB1PPS = 0x23;
I2C2SCLPPS  = 0x09;  

/* RB2 <-> SDA2 */    
RB2PPSbits.RB2PPS = 0x24;
I2C2SDAPPS = 0x0A;

/* Lock PPS */

PPSLOCK = 0x55;
PPSLOCK = 0xAA;
PPSLOCKbits.PPSLOCKED = 0x01;