Wireless Launchpad with the EZ430 RF2500T

Recently, I experimented with the LaunchPad and the EZ430 RF2500T. I plugged an EZ430 RF2500T configured as an access point to the USB port on my laptop. I plugged another EZ430 RF on the J4 connector of the Launchpad. This device was configured as an End Device. On the Launchpad I used the 2231 micro controller and loaded a demo application from TI that reports status of tempature readings (LO, IN or HI).

The purpose of this experiment was to validate that the EZ430 RF2500T can be used for wireless communication with the LaunchPad.

With this setup I was able to wirelessly transmit the tempature status from the LaunchPad to the laptop. Using Hyperterminal I was able to view the data transmitted by the EZ430 RF2500T.

You can find the code for the EZ430 RF2500T access point and end device by downloading TI's EKG-Based Heart-Rate Monitor Implementation on the LaunchPad Value Line Development Kit Using the
MSP430G2452 MCU application demo source. The code for the wireless devices will work right out of the box without modification. I used IAR Kickstart to load the access point and end-device projects on a pair of the EZ430 RF2500T's. Since I did not have the hardware setup for the Heart Rate monitor I loaded the TI demo code shown here on the LaunchPad just so that I could get some data to transmit for the test.

//***********************************************************
// Lab7.c Software UART
//
// SFB 10/2010
//***********************************************************

#include

#define TXD BIT1 // TXD on P1.1
#define RXD BIT2 // RXD on P1.2
#define Bitime 13*1 // 0x0D

unsigned int TXByte;
unsigned char BitCnt;

unsigned int TxHI[]={0x48,0x49,0x0A,0x08,0x08};
unsigned int TxLO[]={0x4C,0x4F,0x0A,0x08,0x08};
unsigned int TxIN[]={0x49,0x4E,0x0A,0x08,0x08};

volatile long tempRaw;
volatile long tempSet = 0;
volatile int i;

void FaultRoutine(void);
void ConfigWDT(void);
void ConfigClocks(void);
void ConfigPins(void);
void ConfigADC10(void);
void ConfigTimerA2(void);
void Transmit(void);

void main(void)
{
ConfigWDT();
ConfigClocks();
ConfigPins();
ConfigADC10();
ConfigTimerA2();

while(1)
{
_bis_SR_register(LPM3_bits + GIE); // turn on interrupts and LPM3

if (tempSet == 0)
{
tempSet = tempRaw; // Set reference temp
}
if (tempSet > tempRaw + 5) // test for lo
{
P1OUT = BIT6; // green LED on
P1OUT &= ~BIT0; // red LED off
for (i=0;i<5;i++)
{
TXByte = TxLO[i];
Transmit();
}
}
if (tempSet < tempRaw - 5) // test for hi
{
P1OUT = BIT0; // red LED on
P1OUT &= ~BIT6; // green LED off
for (i=0;i<5;i++)
{
TXByte = TxHI[i];
Transmit();
}
}
if (tempSet <= tempRaw + 2 & tempSet >= tempRaw - 2)
{ // test for in range
P1OUT &= ~(BIT0 + BIT6); // both LEDs off
for (i=0;i<5;i++)
{
TXByte = TxIN[i];
Transmit();
}
}
}
}

void ConfigWDT(void)
{
WDTCTL = WDT_ADLY_250; // <1 sec WDT interval
IE1 |= WDTIE; // Enable WDT interrupt
}

void ConfigClocks(void)
{
if (CALBC1_1MHZ ==0xFF || CALDCO_1MHZ == 0xFF)
FaultRoutine(); // If calibration data is erased
// run FaultRoutine()
BCSCTL1 = CALBC1_1MHZ; // Set range
DCOCTL = CALDCO_1MHZ; // Set DCO step + modulation
BCSCTL3 |= LFXT1S_2; // LFXT1 = VLO
IFG1 &= ~OFIFG; // Clear OSCFault flag
BCSCTL2 = 0; // MCLK = DCO = SMCLK
}

void FaultRoutine(void)
{
P1OUT = BIT0; // P1.0 on (red LED)
while(1); // TRAP
}

void ConfigPins(void)
{
P1SEL |= TXD + RXD; // P1.1 & 2 TA0, rest GPIO
P1DIR = ~(BIT3 + RXD); // P1.3 input, other outputs
P1OUT = 0; // clear output pins
P2SEL = ~(BIT6 + BIT7); // P2.6 and 7 GPIO
P2DIR |= BIT6 + BIT7; // P1.6 and 7 outputs
P2OUT = 0; // clear output pins

}

void ConfigADC10(void)
{
ADC10CTL1 = INCH_10 + ADC10DIV_0; // Temp Sensor ADC10CLK
}

void ConfigTimerA2(void)
{
CCTL0 = OUT; // TXD Idle as Mark
TACTL = TASSEL_2 + MC_2 + ID_3; // SMCLK/8, continuos mode
}

// WDT interrupt service routine
#pragma vector=WDT_VECTOR
__interrupt void WDT(void)
{
ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + ADC10ON;
_delay_cycles(500); // Wait for ADC Ref to settle
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
_delay_cycles(100);
ADC10CTL0 &= ~ENC; // Disable ADC conversion
ADC10CTL0 &= ~(REFON + ADC10ON); // Ref and ADC10 off
tempRaw = ADC10MEM; // Read conversion value
_bic_SR_register_on_exit(LPM3_bits); // Clr LPM3 bits from SR on exit
}

// Function Transmits Character from TXByte
void Transmit()
{
BitCnt = 0xA; // Load Bit counter, 8data + ST/SP
while (CCR0 != TAR) // Prevent async capture
CCR0 = TAR; // Current state of TA counter
CCR0 += Bitime; // Some time till first bit
TXByte |= 0x100; // Add mark stop bit to TXByte
TXByte = TXByte << 1; // Add space start bit
CCTL0 = CCIS0 + OUTMOD0 + CCIE; // TXD = mark = idle
while ( CCTL0 & CCIE ); // Wait for TX completion
}

// Timer A0 interrupt service routine
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
CCR0 += Bitime; // Add Offset to CCR0
if (CCTL0 & CCIS0) // TX on CCI0B?
{
if ( BitCnt == 0)
{
CCTL0 &= ~ CCIE ; // All bits TXed, disable interrupt
}

else
{
CCTL0 |= OUTMOD2; // TX Space
if (TXByte & 0x01)
CCTL0 &= ~ OUTMOD2; // TX Mark
TXByte = TXByte >> 1;
BitCnt --;
}
}
}

This experiment was a success. Some day I will try the EKG Heart rate demo if I can put together the hardware or obtain the demo board at a reasonable price.