SneaKSz
Member
Hi all,
Im setting up a master slave but my slave does not acknowledge. This is the sequence:
start
write address
write data
stop
Ive searched for various solution(e.g. voltage levels , I2C register settings) but I"m unable to find why the slave does not ack. The slave interrupts when receiving data but it does not acknowlegde.
Something else is that the voltage level of SDA is low when not used. The slave default releases the SDA lines.
this is the master init code :
slave
If someone is interested this is the full code :
master
The full code is not important, I just want to figure out why the slave does not acknowledge.
The address in SSPADD and the address that I send from the master are the same.
If someone could help me , I would be very relieved!
Kind regards
Im setting up a master slave but my slave does not acknowledge. This is the sequence:
start
write address
write data
stop
Ive searched for various solution(e.g. voltage levels , I2C register settings) but I"m unable to find why the slave does not ack. The slave interrupts when receiving data but it does not acknowlegde.
Something else is that the voltage level of SDA is low when not used. The slave default releases the SDA lines.
this is the master init code :
Code:
ADCON1=0x00;//Configure A/D
SDA=1; // input
SCL=1;// input
// MSSP registers
SSPCON1=0b00101000; // I²C master mode , SSPEN enable
SSPSTAT=0b10000000; // Slew Rate control (SMP) 100kHz
SSPADD = 199;// 15KHzslave
Code:
// SSPMSK-> No mask
// 7-Bit Slave mode:
//bit 7-1 ADD<6:0>: 7-bit address
SSPADD=0x08; // address
SSPSTAT=0b00000000;
SSPCON1= 0x36; // I2C Slave mode, 7-bit address , SSPEN enable , release clock
//SSPCON2bits.SEN = 0;
// Disable Address 0x0 General Call
SSPCON2bits.GCEN = 0;If someone is interested this is the full code :
master
Code:
void main(void){
Delay10KTCYx(255);// 510ms
init();// setup
//
while(1){
SendStart(); // send S
SendByte2(0x08); // Address READ
SendByte2(0xAA); // send data
SendStop();
Delay10KTCYx(1);// 510ms
}// end while
}// end maim
void init(){
// set SDA port high
SDA=0;
LATBbits.LATB6=1;
ADCON1=0x00;//Configure A/D
SDA=1; // input
SCL=1;// input
// MSSP registers
SSPCON1=0b00101000; // I²C master mode , SSPEN enable
SSPSTAT=0b10000000; // Slew Rate control (SMP) 100kHz
// baud rate 100.000kHz-> 19kHz
SSPADD = 199;// 50KHz WERT NIET
// 149 werkt 20KHZ 99 ook 30 KHz
// IPEN's
//
// RCONbits.IPEN=1; // enable prio
// IPR1bits.RCIP=0;
// serial
Delay10TCY();// wait 14µs
TRISBbits.TRISB7=0;//TX
TRISBbits.TRISB5=1;///RX
ANSELHbits.ANS11=0; // RB5 digital IO
Delay10TCY();// wait 14µs
TXSTA=0x20;// enable transmit
SPBRG=19; // 9600 bps
RCSTA=0x90;//enable receive + serial port.
TXSTAbits.TXEN=1;
PIR1bits.RCIF=0;
TXSTAbits.SYNC;
RCSTAbits.SPEN;
RCSTAbits.CREN;
PIE1bits.RCIE=1;
PIR1bits.RCIF=0;
INTCONbits.GIE=1;
INTCONbits.PEIE=1;
}
void I2CFAIL(){
SSPCON2bits.PEN=1;
}
void ACKSTAT(){
if ( SSPCON2bits.ACKSTAT==1){ // check ackstat
I2CFAIL(); // STOP
}
}
void Nack(){
SSPCON2bits.ACKDT=1;
SSPCON2bits.ACKEN=1;
}
void SSPFlag() {
while(PIR1bits.SSPIF==0); // wait until sent
PIR1bits.SSPIF=0; // set low
}
void SendByte2(unsigned char data){
SSPBUF= data;
SSPFlag();
}The full code is not important, I just want to figure out why the slave does not acknowledge.
The address in SSPADD and the address that I send from the master are the same.
If someone could help me , I would be very relieved!
Kind regards
Last edited: