USI, USCI_B driver for SPI LED (Oasis)

spirilis · November 16, 2012

Wrote a quick driver and a handful of print functions for displaying data on one of the Oasis SPI LED displays from this thread-- http://forum.43oh.co...gment-displays/

You'll notice some crap about #ifdef _MSPRF24_H_ ... that's so that I can reuse my SPI drivers from my nRF24L01+ library with just a minor modification (spi_mode_2() reconfigures them for this chip, spi_mode_0() reconfigures it back for the nRF24L01+)

Also, the various functions take a pointer to the SFR that your STBY line is connected to along with an unsigned 8-bit integer representing the port bit.

E.g.:

oasisdisp_init(&P1OUT, BIT1); // STBY connected to P1.1

Header file - oasisdisp.h


/* oasisdisp.h
*
* Oasis SPI LED driver library
*/

#ifndef _OASISDISP_H_
#define _OASISDISP_H_

#include <stdint.h>

void spi_mode_2();
void spi_mode_0();

#ifndef _MSPRF24_H_
void spi_init();
uint8_t spi_transfer(uint8_t inb);
#endif

/* The volatile unsigned char * plus unsigned char passed includes the SFR for the Port attached
* to the STBY (SPI Chip Select) line of the target display. Pass this along to each call.
*
* Note that in order to talk to this display after we've been talking to other SPI devices, it may
* be necessary to wrap these calls in spi_mode_2() and run spi_mode_0() at the end to reconfigure
* for whichever other devices we have (e.g. nRF24L01+).
*/

void oasisdisp_init(volatile unsigned char *, unsigned char, uint8_t brightness); // Brightness: 0-7
void oasisdisp_write_digit(volatile unsigned char *, unsigned char, uint8_t, uint8_t);
void oasisdisp_write_space(volatile unsigned char *, unsigned char, uint8_t);
void oasisdisp_write_dash(volatile unsigned char *, unsigned char, uint8_t);

void oasisdisp_print_uint(volatile unsigned char *, unsigned char, unsigned int);
void oasisdisp_print_int(volatile unsigned char *, unsigned char, int);

void oasisdisp_print_byte(volatile unsigned char *, unsigned char, uint8_t); // Hex dump of a single byte
void oasisdisp_print_word(volatile unsigned char *, unsigned char, uint16_t); // Hex dump of two bytes

#endif

Library file - oasisdisp.c


/* oasisdisp.c
*
* Driver for Oasis 4-digit 7-segment LED display
*/

#include <msp430.h>
#include "oasisdisp.h"
#include <stdint.h>

const char oasisdisp_DIGITS[16] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f, 0x77, 0x7c, 0x58, 0x5e, 0x79, 0x71};

void spi_mode_2()
{
#ifdef __MSP430_HAS_USI__
   USICTL0 |= USILSB;
   USICTL1 &= ~USICKPH;
   USICKCTL |= USICKPL;
#endif

#ifdef __MSP430_HAS_USCI__
   UCB0CTL0 &= ~(UCCKPH | UCMSB);
   UCB0CTL0 |= UCCKPL;
#endif
}

void spi_mode_0()
{
#ifdef __MSP430_HAS_USI__
   USICTL0 &= ~USILSB;
   USICTL1 |= USICKPH;
   USICKCTL &= ~USICKPL;
#endif

#ifdef __MSP430_HAS_USCI__
   UCB0CTL0 |= UCCKPH | UCMSB;
   UCB0CTL0 &= ~UCCKPL;
#endif

}

// Wrapping this because we don't need this if we are using the msprf24 nRF24L01+ library...
#ifndef _MSPRF24_H_

// USI
#ifdef __MSP430_HAS_USI__
void spi_init()
{
   /* USI SPI setup */
   USICTL0 |= USISWRST;
   USICTL1 = 0;
   USICKCTL = USICKPL | USISSEL_2 | USIDIV_3;  // Clock source = SMCLK/1
   USICTL0 = USIPE7 | USIPE6 | USIPE5 | USIMST | USILSB | USIOE;
   USISR = 0x0000;
}

uint8_t spi_transfer(uint8_t inb)
{
   USISRL = inb;
   USICNT = 8;            // Start SPI transfer
   while ( !(USICTL1 & USIIFG) )
       ;
   USICTL1 &= ~USIIFG;
   return USISRL;
}
#endif

// USCI_B
#ifdef __MSP430_HAS_USCI__
void spi_init()
{
   /* Configure ports on MSP430 device for USCI_B */
   P1SEL |= BIT5 | BIT6 | BIT7;
   P1SEL2 |= BIT5 | BIT6 | BIT7;

   /* USCI-B specific SPI setup */

   UCB0CTL1 |= UCSWRST;
   UCB0CTL0 = UCCKPL | UCMST | UCMODE_0 | UCSYNC;  // SPI mode 0, master
   UCB0BR0 = 0x01;  // SPI clocked at same speed as SMCLK
   UCB0BR1 = 0x00;
   UCB0CTL1 = UCSSEL_2;  // Clock = SMCLK, clear UCSWRST and enables USCI_B module.
}
uint8_t spi_transfer(uint8_t inb)
{
   UCB0TXBUF = inb;
   while ( !(IFG2 & UCB0RXIFG) )  // Wait for RXIFG indicating remote byte received via SOMI
       ;
   return UCB0RXBUF;
}
#endif
//

#endif

void oasisdisp_init(volatile unsigned char *portout, unsigned char bit, uint8_t brightness)
{
   *portout &= ~bit;
   spi_transfer(0x02);
   *portout |= bit;
   *portout &= ~bit;
   spi_transfer(0x40);
   *portout |= bit;
   *portout &= ~bit;
   spi_transfer(0x88 | (brightness & 0x07));
   *portout |= bit;
}

void oasisdisp_write_digit(volatile unsigned char *portout, unsigned char bit, uint8_t digit, uint8_t numeral)
{
   if (digit > 3)
       return;
   *portout &= ~bit;
   spi_transfer(0xC0 + digit*2);

   spi_transfer(oasisdisp_DIGITS[numeral & 0x0F]);
   *portout |= bit;
}

void oasisdisp_write_space(volatile unsigned char *portout, unsigned char bit, uint8_t digit)
{
   if (digit > 3)
       return;
   *portout &= ~bit;
   spi_transfer(0xC0 + digit*2);
   spi_transfer(0x00);
   *portout |= bit;
}

void oasisdisp_write_dash(volatile unsigned char *portout, unsigned char bit, uint8_t digit)
{
   if (digit > 3)
       return;
   *portout &= ~bit;
   spi_transfer(0xC0 + digit*2);
   spi_transfer(0x40);
   *portout |= bit;
}

void oasisdisp_print_uint(volatile unsigned char *portout, unsigned char bit, unsigned int num)
{
   uint8_t force_zero = 0;

   if (num >= 10000) {  // Only 4 digits here, can't display it...
       num -= (num/10000)*10000;
       force_zero = 1;
   }
   if (num >= 1000 || force_zero) {
       oasisdisp_write_digit(portout, bit, 0, num/1000);
       num -= (num/1000)*1000;
       force_zero = 1;
   } else {

       oasisdisp_write_space(portout, bit, 0);
   }
   if (num >= 100 || force_zero) {
       oasisdisp_write_digit(portout, bit, 1, num/100);
       num -= (num/100)*100;
       force_zero = 1;
   } else {
       oasisdisp_write_space(portout, bit, 1);
   }
   if (num >= 10 || force_zero) {
       oasisdisp_write_digit(portout, bit, 2, num/10);
       num -= (num/10)*10;
       force_zero = 1;
   } else {
       oasisdisp_write_space(portout, bit, 2);
   }
   oasisdisp_write_digit(portout, bit, 3, num);
}

void oasisdisp_print_int(volatile unsigned char *portout, unsigned char bit, int num)
{
   uint8_t i, force_zero = 0, negative = 0;

   if (num < 0) {
       // Temporarily using 'negative' to store the digit index for the negative sign
       num = -num;
       if (num >= 100)
           negative = 0;
       else if (num >= 10)
           negative = 1;
       else
           negative = 2;
       oasisdisp_write_dash(portout, bit, negative);
       for (i = 0; i < negative; i++)
           oasisdisp_write_space(portout, bit, i);

       if (num >= 10000) {

           num -= (num/10000)*10000;
           force_zero = 1;
       }
       if (num >= 1000) {
           num -= (num/1000)*1000;
           force_zero = 1;
       }
       negative = 1;
   }
   if (num >= 10000) {  // Only 4 digits here, can't display it...
       num -= (num/10000)*10000;
       force_zero = 1;
   }
   if (!negative && (num >= 1000 || force_zero)) {
       oasisdisp_write_digit(portout, bit, 0, num/1000);
       num -= (num/1000)*1000;
       force_zero = 1;
   } else {
       if (!negative)
           oasisdisp_write_space(portout, bit, 0);
   }
   if (num >= 100 || force_zero) {
       oasisdisp_write_digit(portout, bit, 1, num/100);
       num -= (num/100)*100;
       force_zero = 1;
   } else {
       if (!negative)
           oasisdisp_write_space(portout, bit, 1);
   }
   if (num >= 10 || force_zero) {
       oasisdisp_write_digit(portout, bit, 2, num/10);
       num -= (num/10)*10;
       force_zero = 1;
   } else {
       if (!negative)
           oasisdisp_write_space(portout, bit, 2);
   }

   oasisdisp_write_digit(portout, bit, 3, num);
}

void oasisdisp_print_byte(volatile unsigned char *portout, unsigned char bit, uint8_t 
{
   oasisdisp_write_space(portout, bit, 0);
   oasisdisp_write_space(portout, bit, 1);
   oasisdisp_write_digit(portout, bit, 2, (b >> 4) & 0x0F);
   oasisdisp_write_digit(portout, bit, 3, b & 0x0F);
}

void oasisdisp_print_word(volatile unsigned char *portout, unsigned char bit, uint16_t 
{
   oasisdisp_write_digit(portout, bit, 0, (b >> 12) & 0x0F);
   oasisdisp_write_digit(portout, bit, 1, (b >> 8) & 0x0F);
   oasisdisp_write_digit(portout, bit, 2, (b >> 4) & 0x0F);
   oasisdisp_write_digit(portout, bit, 3, b & 0x0F);
}

spirilis · November 16, 2012

Example program, just displays four 9's:


/* Four-Nines
* Connect to an Oasis SPI LED display and display four 9's
*/

#include <msp430.h>
#include <stdint.h>
#include "oasisdisp.h"

int main()
{
   WDTCTL = WDTPW | WDTHOLD;
   DCOCTL = CALDCO_16MHZ;
   BCSCTL1 = CALBC1_16MHZ;
   BCSCTL2 = DIVS_2; // SMCLK = 8MHz

   P1DIR |= BIT1;
   P1OUT |= BIT1;
   P1SEL &= ~BIT1;
   P1SEL2 &= ~BIT1;

   spi_init();
   spi_mode_2();
   spi_transfer(0x00); // Strawman xfer to cover G2452 errata USI5

   oasisdisp_init(&P1OUT, BIT1, 7);

   oasisdisp_print_int(&P1OUT, BIT1, 9999);

   LPM4;
   return 0;
}

spirilis · November 16, 2012

Another example, printing a hex word to the display (a pointer):


/* Pointer-Lib
* Connect to an Oasis SPI LED display and display the hex pointer address for a variable
*/

#include <msp430.h>
#include <stdint.h>
#include "oasisdisp.h"

int main()
{
   uint8_t biznatch;

   WDTCTL = WDTPW | WDTHOLD;
   DCOCTL = CALDCO_16MHZ;
   BCSCTL1 = CALBC1_16MHZ;
   BCSCTL2 = DIVS_2;  // SMCLK = 8MHz
   BCSCTL3 = LFXT1S_2;  // ACLK = VLO
   __delay_cycles(8000);     // Wait for VLO settling
   while (BCSCTL3 & LFXT1OF)
       ;

   P1DIR |= BIT1;
   P1OUT |= BIT1;
   P1SEL &= ~BIT1;
   P1SEL2 &= ~BIT1;

   spi_init();
   spi_mode_2();
   spi_transfer(0x00);  // Strawman xfer to cover G2452 errata USI5

   oasisdisp_init(&P1OUT, BIT1, 7);

   oasisdisp_print_word(&P1OUT, BIT1, (uint16_t) &biznatch);

   LPM4;
   return 0;
}

Pic of this example:

spirilis · November 16, 2012

Zip file of the code:

(deleted, check bugfix below)

oasisdisp.zip

spirilis · November 16, 2012

Numbers > 9999 get truncated (so 65535 shows as 5535), negative numbers > 999 get truncated (so -9999 shows as -999)

Uhm, minor bug- -10000 shows as -..0 where ".." is whatever was there before. I'll fix that...

spirilis · November 16, 2012

Fixed code-

oasisdisp.zip

spirilis · November 16, 2012

No support for the colon right now, but I don't really intend to use it... maybe I'll add that later.

spirilis · November 16, 2012

Tossed this up on github-

https://github.com/spirilis/oasisdisp

Also added an oasisdisp_off() function.

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USI, USCI_B driver for SPI LED (Oasis)

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