MSP432 CS-Pin

Christoph,

the CS select pin of your SD-card is a simple input. The SD card is active when CS is low and inactive when it is high. So any GPIO pin of the MSP432 configured as output can act as the driving pin for CS of the SD-card. You won't find a dedicated pin that is exclusively used as CS. No microprocessor has that - it is always a free pin of your choice.

There is a STE pin of the USCI module that can be used as an automatically driven CS, but this will often cost you one special function of another USCI module. But I'm not sure if it is the same for the MSP432 at the moment.

Normally you use a normal GPIO. Before sending your data you enable the slave by PxOUT &= ~BIT; and disable it by PxOUT |= BIT; after transmission is finished.

Dennis

Hi Dennis,

Thank you for fast answer. For my project I used the SD Card from Adafruit (www.exp-tech.de/.../adafruit-microsd-card-breakout-board) in combination with the Code from 43oh ( 43oh.com/.../). After a short modification of the code I was able to compile the code and to transmit the code on the msp432.

But the project didn't work well because no file was created on the SD Card. So i suggest that the cs-pin wasn't well configured.

Greetings,
Chris

Then upload a schematic and your source code and we will see.

I wired the board with the msp432 as described on the Quick Start Guide from TI (www.ti.com/.../slau596.pdf). The source code :

#include <pfatfs.h>
#include <pffconf.h>

/*----------------------------------------------------------------------*/
/* Petit FatFs sample project for generic uC (C)ChaN, 2010 */
/*----------------------------------------------------------------------*/
/*-----------------------------------------------------------------------
Ported to Energia by calinp
Copy the file LOG.txt from this file's location to the root of the
SD-Card.

12/21/2013
Modified by bluehash(43oh) to log temperature data from the MSP430G2553
internal temperature sensor and log it to a file on the SD-Card
References:
forum.43oh.com/.../
*/


#include "SPI.h"
#include "pfatfs.h"

#define cs_pin 8 // chip select pin
#define read_buffer 128 // size (in bytes) of read buffer
#define LOG_DELAY 5000 // 5000ms -> 5sec

unsigned short int bw, br;//, i;
char buffer[read_buffer];
int rc;
DIR dir; /* Directory object */
FILINFO fno; /* File information object */

uint32_t ui32_ReadTemp = 0;
uint8_t StringLength = 0;
char buf[30];
uint32_t counter = 0;
uint32_t AccStringLength = 0;

void setup()
{
pinMode(PUSH2, INPUT_PULLUP);
Serial.begin(9600); // initialize the serial terminal
analogReference(INTERNAL1V5);
analogRead(TEMPSENSOR); // first reading usually wrong
FatFs.begin(cs_pin); // initialize FatFS library calls
Serial.print("\n\n\n MSP430 Temperature Logger \n\r");
Serial.println("Press S2 button to start...");
while(digitalRead(PUSH2)==1){}
delay(100);
while(digitalRead(PUSH2)==0){}
}

/* Stop with dying message */
void die ( int pff_err )
{
Serial.println();
Serial.print("Failed with rc=");
Serial.print(pff_err,DEC);
for (;;) ;
}

void printDec(uint32_t ui)
{
Serial.print(ui/10, DEC);
Serial.print(".");
Serial.print(ui%10, DEC);
}

/*-----------------------------------------------------------------------*/
/* Program Main */
/*-----------------------------------------------------------------------*/
void loop()
{
#if 0
Serial.println();
Serial.println("Press button to start...");
while(digitalRead(PUSH2)==1){}
delay(100);
while(digitalRead(PUSH2)==0){}
#endif

ui32_ReadTemp = ((uint32_t)analogRead(TEMPSENSOR)*27069 - 18169625) *10 >> 16;

#if DEBUG
Serial.println();
Serial.println("Opening log file to write temperature(LOG.txt).");
delay(100);
#endif

rc = FatFs.open("LOG.TXT");
if (rc) die(rc);

delay(100);
bw=0;
ui32_ReadTemp = ((uint32_t)analogRead(TEMPSENSOR)*27069 - 18169625) *10 >> 16;
sprintf( buf, "%lu Current temperature is %lu.%lu\r\n", counter, ui32_ReadTemp/10, ui32_ReadTemp%10 );
counter++;
StringLength = strlen(buf);
Serial.println(buf);

#if DEBUG
Serial.print(StringLength, DEC);
Serial.println();
Serial.print(AccStringLength, DEC);
#endif

rc = FatFs.lseek( AccStringLength );
if (rc) die(rc);
AccStringLength = AccStringLength + 512;
rc = FatFs.write(buf, StringLength,&bw);
if (rc) die(rc);
rc = FatFs.write(0, 0, &bw); //Finalize write
if (rc) die(rc);
rc = FatFs.close(); //Close file
if (rc) die(rc);


#if READ
delay(100);
Serial.println();
Serial.println("Read Temp data from the log file (LOG.txt).");
delay(100);
rc = FatFs.open("LOG.TXT");
if (rc) die(rc);

delay(100);
for (;;) {
rc = FatFs.read(buffer, sizeof(buffer), &br); /* Read a chunk of file */
if (rc || !br) break; /* Error or end of file */
for (uint16_t i = 0; i < br; i++) /* Type the data */
Serial.print(buffer[i]);
delay(100);
}
if (rc) die(rc);
#endif

// Log delay
delay(LOG_DELAY);
}

SPI MOSI --> P1.6 (MSP432)
SPI MISO --> P1.7 (MSP432)
SPI CS --> P5.2 (MSP432)
5 V --> 5V (MSP432)
GND -->GND (MSP432)

I think I have to change the CS_pin from 8 to the P 5.2.
Or am I wrong?