add frequency option

SPI.c

@@ -1,17 +1,17 @@
 #include <msp430.h>
 #include "SPI.h"
 
-uchar SPI_CS;
+uchar SPI_CS = 0;
 
 int SPIInit(){
 
   UCA0CTL1 = UCSWRST;
 
   // setup A0 for SPI
-  UCA0CTL0 = SPI_Mode3 | UCMSB | UCMST | (0x10 << 1) | UCSYNC;
+  UCA0CTL0 = UCMSB | UCMST | (0x10 << 1) | UCSYNC;
   UCA0CTL1 |= UCSSEL_2;
-  UCA0BR1 = 0; //TODO: set corect frequency
-  UCA0BR0 = 4;
+  UCA0BR1 = 0;
+  UCA0BR0 = 16; // 1 MHz
 
 
   // config port
@@ -23,8 +23,8 @@ int SPIInit(){
   UCA0CTL1 &= ~UCSWRST;
 
   // enable interrupts
-  IE2 |= UCA0TXIE;
-  IFG2 &= ~UCA0TXIFG;
+  // IE2 |= UCA0TXIE;
+  // IFG2 &= ~UCA0TXIFG;
 
   // set initial values for vars
   SPI_packetC = 0;
@@ -35,31 +35,56 @@ int SPIInit(){
   return 0;
 }
 
-void SPISend(){
-  P1OUT &= ~SPI_CS;
-  UCA0TXBUF = SPI_packet[SPI_packetC];
-}
+//TODO: add clock freqency configuration
+/* 
+ * do some configuration before sending the data.
+ * 
+ * @arg uchar cs: the bit of port 1 connected to the chip select pin of target device
+ * @arg enum SPI_Mode: the SPI modus (clock pase and polarity)
+ * @arg enum SPI_clock: the clock freqency
+ */
+void SPIInitSend(uchar cs, enum SPI_Mode mode, enum SPI_Clock clk){
+  //TODO: add a clock as powerefficent delay
+  while(SPI_CS != 0); // wait for last transmit to be done
       
-void SPIInitSend(uchar cs, enum SPI_Mode mode){
-  while(SPI_CS != 0)
-      //TODO: search for a more power effient way for a delay
-      __delay_cycles (16000);
+  // set clock frequency
+  UCA0BR0 = clk;
 
+  // set SPI mode
+  UCA0CTL0 &= 0x3F; // set mode bits to 0
   UCA0CTL0 |= mode;
-  UCA0CTL0 &= ~mode ^ 0xC0;
+
+  // save chip select
   SPI_CS = cs;
 }
 
-#pragma vector = USCIAB0TX_VECTOR
-__interrupt void ISR_EUSCI_A0(){
-  SPI_packet[SPI_packetC] = UCA0RXIFG;
-  if(SPI_packetC == 4){
-    P1OUT |= SPI_CS;
-    SPI_packetC = 0;
-    IFG2 &= ~UCA0TXIFG;
-    SPI_CS = 0;
-  }else{
-    SPI_packetC++;
+//TODO: make it asyncronily with interupt. 
+/*
+ * Send the packet stored in SPI_packet. it start from SPI_packetC to the last byte
+ */
+void SPISend(){
+  P1OUT &= ~SPI_CS; // select slave
+
+  while(SPI_packetC < 5){
+    // send one byte
     UCA0TXBUF = SPI_packet[SPI_packetC];
+
+    //TODO: fix the delay! it's to short with low data speeds
+    if(UCA0BR0 > 4) 
+      // if de frequency lower than 4 MHz do a manual delay. this is a workaround for the to short delay
+      // this works down to 1 MHz
+      __delay_cycles(129);
+    else
+      while(UCB0STAT & UCBUSY); // wait for SPI TX/RX to finish
+
+    // save recieved data
+    SPI_packet[SPI_packetC] = UCA0RXIFG;
+
+    // increase counter for next byte
+    SPI_packetC++;
   }
+
+  SPI_packetC = 0; // recet counter
+  P1OUT |= SPI_CS; // deselect slave
+  SPI_CS = 0;
 }

SPI.h

@@ -11,12 +11,13 @@
 #include "typedefExtention.h"
 
 enum SPI_Mode {SPI_Mode0=0b00<<6, SPI_Mode1=0b10<<6, SPI_Mode2=0b11<<6, SPI_Mode3=0b01<<6};
+enum SPI_Clock {SPI_Clock_1MHz=16, SPI_Clock_2MHz=8, SPI_Clock_4MHz=4, SPI_Clock_8MHz=2};
 
 uchar SPI_packet[5];
 char  SPI_packetC;
 
 int   SPIInit();
 void  SPISend();
-void  SPIInitSend(uchar cs, enum SPI_Mode mode);
+void  SPIInitSend(uchar cs, enum SPI_Mode mode, enum SPI_Clock clk);
 
 #endif /* SPI_C_ */

motionController.c

@@ -88,7 +88,7 @@ void MC_write(uchar addr, ulong data) {
   char i;
 
   // wait for SPI bus to be available
-  SPIInitSend(MC_CS, SPI_Mode3);
+  SPIInitSend(MC_CS, SPI_Mode3, SPI_Clock_1MHz);
 
   // set write bit to write
   addr &= ~0x01;
@@ -109,7 +109,7 @@ ulong MC_read(unsigned char addr) {
   ulong data;
 
   // wait for SPI bus to be available
-  SPIInitSend(MC_CS, SPI_Mode3);
+  SPIInitSend(MC_CS, SPI_Mode3, SPI_Clock_1MHz);
 
   // set write bit to read
   addr |= 0x01;
@@ -119,7 +119,7 @@ ulong MC_read(unsigned char addr) {
   SPISend();
 
   // wait for SPI bus to be available
-  SPIInitSend(MC_CS, SPI_Mode3);
+  SPIInitSend(MC_CS, SPI_Mode3, SPI_Clock_1MHz);
 
   // set write bit to read
   addr |= 0x01;

motorDriver.c

@@ -68,7 +68,7 @@ void MD_write(uchar addr, ulong data) {
   char i;
 
   // wait for SPI bus to be available
-  SPIInitSend(MD_CS, SPI_Mode3);
+  SPIInitSend(MD_CS, SPI_Mode3, SPI_Clock_4MHz);
 
   // set write bit to write
   addr |= 0x80;
@@ -89,7 +89,7 @@ unsigned long MD_read(uchar addr) {
   ulong data;
 
   // wait for SPI bus to be available
-  SPIInitSend(MD_CS, SPI_Mode3);
+  SPIInitSend(MD_CS, SPI_Mode3, SPI_Clock_4MHz);
 
   // set write bit to read
   addr &= ~0x80;
@@ -98,7 +98,7 @@ unsigned long MD_read(uchar addr) {
   SPISend(SPI_Mode3);
 
   // wait for SPI bus to be available
-  SPIInitSend(MD_CS, SPI_Mode3);
+  SPIInitSend(MD_CS, SPI_Mode3, SPI_Clock_4MHz);
   
   SPI_packet[0] = addr;
   SPISend(SPI_Mode3);