Hi!
I have a question regarding the communication between the CC1120 and my MSP430F5438A on my CC1120 DK kit. I am currently developing software for my future MSP430F5506 processor and now I have this DK from TI. I want to communicate with my CC1120 EM and I want to set up this SPI configuration. I have a question regarding this SPI communication. My PCB will have 4 signals to the transceiver (SOMI, SIMO, Clk and CSN) but I do not know which setup this DK kit uses. Is it 3 or 4 wire mode? Can the CC1120 operate in 3-wire mode? I thought it was required to operate with 4-wire mode. I downloaded a 3-wire code example using ccs v5.3 and I would also like some help how to redo this code in order for it to work with this DK. The code looks like this:
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//******************************************************************************
// MSP430F543xA Demo - USCI_A0, SPI 3-Wire Master Incremented Data
//
// Description: SPI master talks to SPI slave using 3-wire mode. Incrementing
// data is sent by the master starting at 0x01. Received data is expected to
// be same as the previous transmission. USCI RX ISR is used to handle
// communication with the CPU, normally in LPM0. If high, P1.0 indicates
// valid data reception. Because all execution after LPM0 is in ISRs,
// initialization waits for DCO to stabilize against ACLK.
// ACLK = ~32.768kHz, MCLK = SMCLK = DCO ~ 1048kHz. BRCLK = SMCLK/2
//
// Use with SPI Slave Data Echo code example. If slave is in debug mode, P1.1
// slave reset signal conflicts with slave's JTAG; to work around, use IAR's
// "Release JTAG on Go" on slave device. If breakpoints are set in
// slave RX ISR, master must stopped also to avoid overrunning slave
// RXBUF.
//
// MSP430F5438A
// -----------------
// /|\| |
// | | |
// --|RST P1.0|-> LED
// | |
// | P3.4|-> Data Out (UCA0SIMO)
// | |
// | P3.5|<- Data In (UCA0SOMI)
// | |
// Slave reset <-|P1.1 P3.0|-> Serial Clock Out (UCA0CLK)
//
//
// M. Morales
// Texas Instruments Inc.
// June 2009
// Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************
#include <msp430.h>
unsigned char MST_Data,SLV_Data;
int main(void)
{
WDTCTL = WDTPW+WDTHOLD; // Stop watchdog timer
P1OUT |= 0x02; // Set P1.0 for LED
// Set P1.1 for slave reset
P1DIR |= 0x03; // Set P1.0-2 to output direction
P3SEL |= 0x31; // P3.5,4,0 option select
UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
UCA0CTL0 |= UCMST+UCSYNC+UCCKPL+UCMSB; // 3-pin, 8-bit SPI master
// Clock polarity high, MSB
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 0x02; // /2
UCA0BR1 = 0; //
UCA0MCTL = 0; // No modulation
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt
P1OUT &= ~0x02; // Now with SPI signals initialized,
P1OUT |= 0x02; // reset slave
__delay_cycles(100); // Wait for slave to initialize
MST_Data = 0x01; // Initialize data values
SLV_Data = 0x00; //
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = MST_Data; // Transmit first character
__bis_SR_register(LPM0_bits + GIE); // CPU off, enable interrupts
}
#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
{
switch(__even_in_range(UCA0IV,4))
{
case 0: break; // Vector 0 - no interrupt
case 2: // Vector 2 - RXIFG
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
if (UCA0RXBUF==SLV_Data) // Test for correct character RX'd
P1OUT |= 0x01; // If correct, light LED
else
P1OUT &= ~0x01; // If incorrect, clear LED
MST_Data++; // Increment data
SLV_Data++;
UCA0TXBUF = MST_Data; // Send next value
__delay_cycles(40); // Add time between transmissions to
// make sure slave can process information
break;
case 4: break; // Vector 4 - TXIFG
default: break;
}
}
What do I need to do in order for this one to work with the CC1120DK? The ports used to communicate with the CC1120EM through SPI is P3.0 - P3.3 on the DK board. Never mind the increment stuff as this will not be used I just want to know how I can initialize the SPI correctly.