Added support for MSP430G2553

Added set of #defines to differentiate between the originally targeted
MSP430FR5739 and the MSP430G2553 that I wanted to use (because it
currently comes with the TI MSP430 Launchpad). MSP430G2553 has some
different register names and no DMA support.

README.md

@@ -16,6 +16,8 @@ One 3-bit and one 4-bit encoding was implemented for a SPI clock speed as low as
  * __
  * ONE : 110 |_
  *
+ * SPI Clock around 2.66MHz
+ *
  * the bti in the middle defines the value
  *
  * data stream: 0x23 0 0 1 0 0 0 1 1

main.c

@@ -4,14 +4,21 @@
 #define NUMBEROFLEDS 15
 #define ENCODING 3 // possible values 3 and 4
 
+//For MSP430G2553, this works for up to 32 LEDs with encoding of 4, or 39 LEDs with encoding of 3. Beyond that it seems to use too much memory.
+
+/*
+ * In places with preprocessor directives like: #if defined(UCA0CTLW0)
+ * the code is checking to see what capabilities exist for the target microcontroller.
+ * If the value in question is defined, it means that a certain capabilities exist or
+ * register names differ, and code appropriate to the device will be used.
+ */
 
 void configClock(void);
 void configSPI(void);
 void sendBuffer(uint8_t* buffer, ledcount_t ledCount);
 void sendBufferDma(uint8_t* buffer, ledcount_t ledCount);
 void shiftLed(ledcolor_t* leds, ledcount_t ledCount);
 
-
 int main(void) {
 
  // buffer to store encoded transport data
@@ -68,14 +75,14 @@ int main(void) {
  while(1) {
  // blank all LEDs
  fillFrameBufferSingleColor(&blankLed, NUMBEROFLEDS, frameBuffer, ENCODING);
- sendBufferDma(frameBuffer, NUMBEROFLEDS);
+ sendBuffer(frameBuffer, NUMBEROFLEDS);
  __delay_cycles(0x100000);
 
  // Animation - Part1
  // set one LED after an other (one more with each round) with the colors from the LEDs array
  fillFrameBuffer(leds, NUMBEROFLEDS, frameBuffer, ENCODING);
  for(update=1; update <= NUMBEROFLEDS; update++) {
- sendBufferDma(frameBuffer, update);
+ sendBuffer(frameBuffer, update);
  __delay_cycles(0xFFFFF);
  }
  __delay_cycles(0xFFFFFF);
@@ -85,7 +92,7 @@ int main(void) {
  for(update=0; update < 15*8; update++) {
  shiftLed(leds, NUMBEROFLEDS);
  fillFrameBuffer(leds, NUMBEROFLEDS, frameBuffer, ENCODING);
- sendBufferDma(frameBuffer, NUMBEROFLEDS);
+ sendBuffer(frameBuffer, NUMBEROFLEDS);
  __delay_cycles(0x7FFFF);
  }
 
@@ -95,19 +102,19 @@ int main(void) {
  for(colorIdx=0; colorIdx < 0xFF; colorIdx++) {
  led.red = colorIdx + 1;
  fillFrameBufferSingleColor(&led, NUMBEROFLEDS, frameBuffer, ENCODING);
- sendBufferDma(frameBuffer, NUMBEROFLEDS);
+ sendBuffer(frameBuffer, NUMBEROFLEDS);
  __delay_cycles(0x1FFFF);
  }
  for(colorIdx=0; colorIdx < 0xD0; colorIdx++) {
  led.green = colorIdx;
  fillFrameBufferSingleColor(&led, NUMBEROFLEDS, frameBuffer, ENCODING);
- sendBufferDma(frameBuffer, NUMBEROFLEDS);
+ sendBuffer(frameBuffer, NUMBEROFLEDS);
  __delay_cycles(0x2FFFF);
  }
  for(colorIdx=0; colorIdx < 0x50; colorIdx++) {
  led.blue = colorIdx;
  fillFrameBufferSingleColor(&led, NUMBEROFLEDS, frameBuffer, ENCODING);
- sendBufferDma(frameBuffer, NUMBEROFLEDS);
+ sendBuffer(frameBuffer, NUMBEROFLEDS);
  __delay_cycles(0x3FFFF);
  }
  __delay_cycles(0xFFFFF);
@@ -127,61 +134,101 @@ void shiftLed(ledcolor_t* leds, ledcount_t ledCount) {
 }
 
 // copy bytes from the buffer to SPI transmit register
-// should be reworked to use DMA
 void sendBuffer(uint8_t* buffer, ledcount_t ledCount) {
- uint16_t bufferIdx;
- for (bufferIdx=0; bufferIdx < (ENCODING * sizeof(ledcolor_t) * ledCount); bufferIdx++) {
- while (!(UCA0IFG & UCTXIFG)); // wait for TX buffer to be ready
- UCA0TXBUF_L = buffer[bufferIdx];
- }
- __delay_cycles(300);
-}
-
-void sendBufferDma(uint8_t* buffer, ledcount_t ledCount) {
- DMA0SA = (__SFR_FARPTR) buffer; // source address
+#if defined(DMA0CTL_) //used for MSP430FR5739 (and similar)
+ //If DMA exists for the microcontroller, this code will make use of it
+ DMA0SA = (__SFR_FARPTR) buffer; // source address
  DMA0DA = (__SFR_FARPTR) &UCA0TXBUF_L; // destination address
  // single transfer, source increment, source and destination byte access, interrupt enable
- DMACTL0 = DMA0TSEL__UCA0TXIFG; // DMA0 trigger input
+ DMACTL0 = DMA0TSEL__UCA0TXIFG;  // DMA0 trigger input
  DMA0SZ = (ENCODING * sizeof(ledcolor_t) * ledCount);
- DMA0CTL = DMADT_0 | DMASRCINCR_3 | DMASRCBYTE | DMADSTBYTE | DMAEN; //| DMAIE;
+ DMA0CTL = DMADT_0 | DMASRCINCR_3 | DMASRCBYTE | DMADSTBYTE | DMAEN;
 
  //start DMA
  UCA0IFG ^= UCTXIFG;
  UCA0IFG ^= UCTXIFG;
+#else
+ uint16_t bufferIdx;
+ for (bufferIdx=0; bufferIdx < (ENCODING * sizeof(ledcolor_t) * ledCount); bufferIdx++) {
+ // wait for TX buffer to be ready
+ #if defined(UCA0TXIFG) //used for MSP430G2553 (and similar)
+ while (!(IFG2 & UCA0TXIFG));
+ #elif defined(UCA0IFG) //used for MSP430FR5739 (and similar)
+ while (!(UCA0IFG & UCTXIFG));
+ #endif
+
+ #if defined(UCA0TXBUF_) //used for MSP430FR5739 (and similar) where the USCI TX buffer is two bytes in size
+ UCA0TXBUF_L = buffer[bufferIdx];
+ #else //used for MSP430G2553 and similar where the USCI TX buffer is one byte in size
+ UCA0TXBUF = buffer[bufferIdx];
+ #endif
+
+ }
+ __delay_cycles(300);
+#endif
 }
 
-// configure MCLK and SMCLK to be sourced by DCO with a frequency of
-// 8Mhz (3-bit encoding)
-// 6.7MHz (4-bit encoding)
+
+
+
+
 void configClock(void) {
+#if defined(CSCTL0_) //used for MSP430FR5739 (and similar)
+ // configure MCLK and SMCLK to be sourced by DCO with a frequency of
+ // 8Mhz (3-bit encoding)
+ // 6.7MHz (4-bit encoding)
  CSCTL0_H = 0xA5;
-#if ENCODING == 3
- CSCTL1 = DCOFSEL_3;  // DCO frequency setting = 8MHz
-#else
- CSCTL1 = DCOFSEL_2;  // DCO frequency setting = 6.7MHz
-#endif
+ #if ENCODING == 3
+ CSCTL1 = DCOFSEL_3; // DCO frequency setting = 8MHz
+ #else
+ CSCTL1 = DCOFSEL_2; // DCO frequency setting = 6.7MHz
+ #endif
  CSCTL2 = SELS__DCOCLK + SELM__DCOCLK;
  CSCTL3 = DIVS__1 + DIVM__1;
+#else //used for MSP430G2553 (and similar)
+ // configure MCLK and SMCLK to be sourced by DCO with a frequency of 16Mhz
+ BCSCTL1 = CALBC1_16MHZ; //DCO frequency setting 16MHz
+ DCOCTL = CALDCO_16MHZ;
 
+ BCSCTL2 = DIVS_0 + DIVM_0 + SELM_0; //set MCLK and SMCLK to the DCO clock of 16MHz
+#endif
 }
 
 void configSPI(void) {
+
+#if defined(UCA0CTLW0) //used for MSP430FR5739 (and similar)
  UCA0CTLW0 |= UCSWRST; // **Put state machine in reset**
  UCA0CTLW0 |= UCMST + UCSYNC + UCCKPL + UCMSB; // 3-pin, 8-bit SPI master
  // Clock polarity high, MSB
  UCA0CTLW0 |= UCSSEL__SMCLK; // SMCLK
 
-#if ENCODING == 3
- UCA0BR0 = 3; // SPICLK 8MHz/3 = 2.66MHz
+ #if ENCODING == 3
+ UCA0BR0 = 3;  // SPICLK 8MHz/3 = 2.66MHz
  UCA0BR1 = 0;
-#else
- UCA0BR0 = 2; // SPICLK 6.7MHz/2 = 3.35MHz
+ #else
+ UCA0BR0 = 2;  // SPICLK 6.7MHz/2 = 3.35MHz
  UCA0BR1 = 0;
-#endif
+ #endif
  UCA0MCTLW = 0; // No modulation
  UCA0CTLW0 &= ~UCSWRST;
+#else //used for MSP430G2553 (and similar)
+ UCA0CTL1 |= UCSWRST; //hold USCI A0 in reset
+
+ UCA0CTL0 = UCCKPH | UCMSB | UCMST | UCMODE_0 | UCSYNC;
+ UCA0CTL1 = UCSSEL_2 | UCSWRST; // Clock from SMCLK; hold in reset
+ #if ENCODING == 3
+ UCA0BR0 = 6; // SPICLK 16MHz/6 = 2.66MHz
+ UCA0BR1 = 0;
+ #else
+ UCA0BR0 = 5; // SPICLK 16MHz/5 = 3.2MHz
+ UCA0BR1 = 0; // 3.2MHz provides 0.31us per bit, so 4 bit operation results in
+ // 0.31us (within 0.15us of both 0.40us and 0.45us) and and 0.93us (within 0.15us of 0.80us and 0.85us)
+ #endif
+
+ P1SEL = BIT1 + BIT2; //need to set P1SEL to assign pins to the USCI peripheral
+ P1SEL2 = BIT1 + BIT2; //need to set P1SEL to assign pins to the USCI peripheral
+
+ UCA0CTL1 &= ~UCSWRST; //release USCI A0 to operate normally
+#endif
 
- // UCB0SIMO = LED data signal on P2.0
- P2SEL0 &= ~BIT0;
- P2SEL1 |= BIT0;
 }

ws2812/ws2812.c

@@ -6,6 +6,7 @@
  *
  */
 
+#define BIT0 0x01
 
 #include "ws2812.h"
 
@@ -112,22 +113,22 @@ void encodeData3bit(ledcolor_t* led, uint8_t* output) {
  // right shift bits
  shiftRegister = grbLED[colorIdx];
  shiftRegister >>= 1; // 1 shift from original
- output[outputIdx+0] |= (shiftRegister & BIT6); // source bit 7
- output[outputIdx+1] |= (shiftRegister & BIT2); // source bit 3
+ output[outputIdx+0] |= (shiftRegister & 0x40); // shiftregister bit 6, source bit 7
+ output[outputIdx+1] |= (shiftRegister & 0x04); // shiftregister bit 2, source bit 3
  shiftRegister >>= 2; // 3 shifts from original
- output[outputIdx+0] |= (shiftRegister & BIT3); // source bit 6
+ output[outputIdx+0] |= (shiftRegister & 0x08); // shiftregister bit 3, source bit 6
  shiftRegister >>= 2; // 5 shifts from original
- output[outputIdx+0] |= (shiftRegister & BIT0); // source bit 5
+ output[outputIdx+0] |= (shiftRegister & 0x01); // shiftregister bit 0, source bit 5
 
  // left shift bits
  shiftRegister = grbLED[colorIdx];
  shiftRegister <<= 1; // 1 shift from original
- output[outputIdx+1] |= (shiftRegister & BIT5); // source bit 4
- output[outputIdx+2] |= (shiftRegister & BIT1); // source bit 0
+ output[outputIdx+1] |= (shiftRegister & 0x20); // shiftregister bit 5, source bit 4
+ output[outputIdx+2] |= (shiftRegister & 0x02); // shiftregister bit 1, source bit 0
  shiftRegister <<= 2; // 3 shifts from original
- output[outputIdx+2] |= (shiftRegister & BIT4); // source bit 1
+ output[outputIdx+2] |= (shiftRegister & 0x10); // shiftregister bit 4, source bit 1
  shiftRegister <<= 2; // 5 shifts from original
- output[outputIdx+2] |= (shiftRegister & BIT7); // source bit 2
+ output[outputIdx+2] |= (shiftRegister & 0x80); // shiftregister bit 7, source bit 2
 
  outputIdx += 3; // next three bytes (color)
  }

ws2812/ws2812.h

@@ -1,13 +1,6 @@
 #include <stdint.h>
 
-#define BIT0 0x01
-#define BIT1 0x02
-#define BIT2 0x04
-#define BIT3 0x08
-#define BIT4 0x10
-#define BIT5 0x20
-#define BIT6 0x40
-#define BIT7 0x80
+//removed the BIT0, BIT1, etc. #defines as it conflicted with those in the microcontroller-specific header files
 
 typedef struct {
  uint8_t red;