MSP430F5438A: I2C communication error

Rowshon Munny

Hello,

I am trying to communicate with the MAX30101 sensor through an I2C protocol. Here the master is MSP430F5438A, and my IDE is Code Composer studio. From the sensor, I am trying to get how many samples I have to read. I am building the code from scratch. For my purpose, I have to read the WR_PTR and RD_PTR data fro sensor. I'm supposed to get some value in between 1 to 32, but I am always getting 0 for both. Anyone can answer is my I2C code section is correct or not? If not how can I fix it?

Following is the datasheet of the sensor (If necessary):

datasheets.maximintegrated.com/.../MAX30101.pdf

My Code:

#include <msp430.h>

#include <msp430f5438a.h>

#include <string.h>

#define MAX30101_I2C_ADDRESS 0x57

#define MAX30101_REG_INT_STS1 0x00

#define MAX30101_REG_INT_STS2 0x01

#define MAX30101_REG_INT_EN1 0x02

#define MAX30101_REG_INT_EN2 0x03

#define MAX30101_REG_FIFO_WR 0x04

#define MAX30101_REG_FIFO_OVF 0x05

#define MAX30101_REG_FIFO_RD 0x06

#define MAX30101_REG_FIFO_DATA 0x07

#define MAX30101_REG_FIFO_CFG 0x08

#define MAX30101_REG_MODE_CFG 0x09

#define MAX30101_REG_SPO2_CFG 0x0a

#define MAX30101_REG_LED1_PA 0x0c

#define MAX30101_REG_LED2_PA 0x0d

#define MAX30101_REG_LED3_PA 0x0e

#define MAX30101_REG_PILOT_PA 0x10

#define MAX30101_REG_MULTI_LED 0x11

#define MAX30101_REG_TINT 0x1f

#define MAX30101_REG_TFRAC 0x20

#define MAX30101_REG_TEMP_CFG 0x21

#define MAX30101_REG_PROX_INT 0x30

void Clock_setup(); // default

void MAX30101_setup(); // Sensor config setup

void I2C_setup();

void sendByte(char register_add, char data);

int readByte(char wr_add, char rd_add, char register_add);

void burstRead(char wr_add, char rd_add, char register_add, int no_ofsample);

void FIFO_Clear();

char LED1 [96];

char LED2 [96];

char LED3 [96];

long L1[32];

long L2[32];

long L3[32];

int wr;

int rd;

int Ns; // number of available sample

void main()

{

WDTCTL = WDTPW + WDTHOLD;

Clock_setup();

I2C_setup();

//_EINT();

MAX30101_setup();

while(1){

//FIFO_Clear();

wr= readByte(0xAE, 0xAF, 0x04); // reading WR_PTR---> I don't know why getting zero // 0xAE= sensor address+write mode, 0xAF= Sensor address+read mode, 0x04= address of write pointer

rd= readByte(0xAE, 0xAF, 0x06); // reading RD_PTR---> I don't know why getting zero // 0x06= address of read pointer

Ns = wr-rd;

if(Ns<0){

Ns+=32;

}

void Clock_setup(){
P11DIR |= BIT2; // check smclk, 1MHz default
P11SEL |= BIT2; // check smclk, 1MHz default
P11DIR |= BIT0; // check aclk, 32.8KHz default
P11SEL |= BIT0; // check aclk, 32.8KHz default
}

void I2C_setup() {

P3SEL |= BIT7; // P3.1(UCB0_SDA), P3.2(UCB0_SCL) // 3.7 UCB1_SDA, 5.4 UCB1_SCL
P5SEL |= BIT4;
UCB1CTL1 |= UCSWRST; // reset enable
UCB1CTL0 = UCMST + UCMODE_3 + UCSYNC; // master + I2C mode + Sync
UCB1CTL1 = UCSSEL_2 + UCSWRST; //use SMCLK + still reset
UCB1BR0 = 10; // default SMCLK 1M/10 = 100KHz
UCB1BR1 = 0; //
UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57
UCB1CTL1 &= ~UCSWRST; // reset clear
// UCB1IE |= UCTXIE + UCRXIE; //TX and RX interrupt enabled
}

// sending a single byte

void sendByte(char register_add, char data){

UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57

UCB1CTL1 |= UCTR + UCTXSTT; // I2C transmit (write) mode + generating START condition

UCB1TXBUF = register_add; //register address to get back data

while(UCB1CTL1 & UCTXSTT); //wait till START condition is cleared

while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent

UCB1TXBUF = data; //send data to register

while(!(UCB1IFG & UCTXIFG)); //wait until data got sent

UCB1CTL1 |= UCTXSTP; //generate a STOP condition

while(UCB1CTL1 & UCTXSTP); //wait until stop condition got sent

}

//Single Byte Receive (RX)

int readByte(char wr_add, char rd_add, char register_add){

int rx_byte;

//UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57

UCB1CTL1 |= UCTXSTT + UCTR; // Generating START + I2C transmit (write)

UCB1TXBUF = wr_add; //write register address

while( UCB1CTL1 & UCTXSTT); //wait till START condition is cleared

while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent

UCB1TXBUF = register_add; //write register address

while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent

//UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57

UCB1CTL1 |= UCTXSTT; //generate RE-START

UCB1TXBUF = rd_add; //write register address

while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent

UCB1CTL1 &=~ UCTR; //receive mode

while( UCB1CTL1 & UCTXSTT); //wait till START condition is cleared

//while(!(UCB1IFG & UCRXIFG)); //wait while the Byte has being read

rx_byte = UCB1RXBUF; //read byte

while(!(UCB1IFG & UCRXIFG)); //wait while the Byte has being read

UCB0CTL1 |= UCTXNACK; //generate a NACK

UCB1CTL1 |= UCTXSTP; //generate stop condition

while(UCB1CTL1 & UCTXSTP); //wait till stop condition got sent

return rx_byte;

}

void MAX30101_setup(){
sendByte(0x08, 0x40); // Sample avg.=4
sendByte(0x09, 0x07); // Mode= Multi
sendByte(0x0A, 0x0F); //ADC range= 2048, sample rate=400, PW control=411
sendByte(0x0C, 0x1F); // RED pulse amplitude
sendByte(0x0D, 0x1F); // IR pulse amplitude
sendByte(0x0E, 0x1F); // GREEN pulse amplitude
sendByte(0x10, 0x1F); // Proximity pulse amplitude
sendByte(0x11, 0x77); // SLOT 01 and 02
sendByte(0x12, 0x07); // Slot 03
FIFO_Clear();
}

void FIFO_Clear(){
sendByte(0x04, 0x00); // FIFO WR_PTR clear
sendByte(0x05, 0x00); // FIFO over flow counter clear
sendByte(0x06, 0x00); // FIFO RD_PTR clear
}

over 7 years ago

0 Andre Frantzke over 7 years ago

TI__Expert 5490 points

Hi,

To clarify your problem I have some questions.

Do you get a response from the MAX30101 at all?
Why are you enabling interrupts if you don't have an ISR defined?
Your Clock_setup(); and I2C_setup(); functions are missing.

Andre

0 Rowshon Munny over 7 years ago in reply to Andre Frantzke

Intellectual 390 points

Hello,
Thank you for your response.
Sorry, I was copying and pasting it from my IDE and that's why missed those functions. Edited now.
Commented _EINT() because I am not using interrupt
I haven't get any response yet. (Not sure what type of response you are talking about but I am sure the sensor is good because I tested some Arduino code in it and it responded)

Thanks.

0 Andre Frantzke over 7 years ago in reply to Rowshon Munny

TI__Expert 5490 points

Hi,

With response I mean if you can read out any value. In your code you are doing a lot of configuration, so I would go step by step. See if you can read properly, then write and check if the write was successful. Thus I recommend to start with a much simpler program and then step by step get more complex. Can you please check the waveforms with an oscilloscope or logic analyzer and compare them with the Arduino waveform?
Is the I2C protocol right?
Are START/STOP conditions correct?
What is the speed of the I2C?
Do you have pull-ups on SCL/SDA ...

Please also check the application note: http://www.ti.com/lit/slaa734 , chapter 5.

Best regards,
Andre

0 Rowshon Munny over 7 years ago in reply to Andre Frantzke

Intellectual 390 points

Hello,

So I trim the code and just trying to read the partID by sending the register address(0xFF) to the sensor. The sensor should return 0x15. But I think I can transfer register address and got the ACK but still not getting anything in the RX buffer. Can you tell me where I'm doing wrong? Is this the problem with the I2C coding?

Here I'm attaching the pictures from the logic analyzer (1=1st byte ,2 = last byte where I sent to read data from the register ). The code for reading the PartID of the sensor is here:

#include <msp430.h>
#include <msp430f5438a.h>
#include <string.h>

#define MAX30101_I2C_ADDRESS 0x57

void Clock_setup(); // default
void I2C_setup();

int readByte(char wr_add, char rd_add, char register_add);

int ID;

void main()
{
WDTCTL = WDTPW + WDTHOLD;
Clock_setup();
I2C_setup();
ID = readByte(0xAE, 0xAF, 0xFF); // 0xFF is the register address for partID

}

void I2C_setup() {

P3SEL |= BIT7; // P3.1(UCB0_SDA), P3.2(UCB0_SCL) // 3.7 UCB1_SDA, 5.4 UCB1_SCL
P5SEL |= BIT4;
UCB1CTL1 |= UCSWRST; // reset enable
UCB1CTL0 = UCMST + UCMODE_3 + UCSYNC; // master + I2C mode + Sync
UCB1CTL1 = UCSSEL_2 + UCSWRST; //use SMCLK + still reset
UCB1BR0 = 10; // default SMCLK 1M/10 = 100KHz.........?
UCB1BR1 = 0; //
UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57
UCB1CTL1 &= ~UCSWRST; // reset clear
// UCB1IE |= UCTXIE + UCRXIE; //TX and RX interrupt enabled
}

//Single Byte Receive (RX)
int readByte(char wr_add, char rd_add, char register_add){
int rx_byte;

//UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57
UCB1CTL1 |= UCTXSTT + UCTR; // Generating START + I2C transmit (write)
UCB1TXBUF = wr_add; //write register address
while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent
while( UCB1CTL1 & UCTXSTT); //wait till START condition is cleared
UCB1TXBUF = register_add; //write register address
while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent
//UCB1I2CSA = MAX30101_I2C_ADDRESS; // MAX30101 7 bit address 0x57
UCB1CTL1 |= UCTXSTT; //generate RE-START
UCB1TXBUF = rd_add; //write register address
while(!(UCB1IFG & UCTXIFG)); //wait until reg address got sent
UCB1CTL1 &=~ UCTR; //receive mode
while( UCB1CTL1 & UCTXSTT); //wait till START condition is cleared
//while(!(UCB1IFG & UCRXIFG)); //wait while the Byte has being read
rx_byte = UCB1RXBUF; //read byte
// while(!(UCB1IFG & UCRXIFG)); //wait while the Byte has being read
UCB1CTL1 |= UCTXNACK; //generate a NACK
UCB1CTL1 |= UCTXSTP; //generate stop condition
while(UCB1CTL1 & UCTXSTP); //wait till stop condition got sent

return rx_byte;
}

Thanks,

Rowshon.

0 Andre Frantzke over 7 years ago in reply to Rowshon Munny

TI__Expert 5490 points

Hi,

have you implemented the protocol according to the MAX30101 data sheet? For a read operation you don't need to send a write register access. Please see below.

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MSP430F5438A: I2C communication error