The SPI Function - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 496

TC72 HCS12 MCU

V DD

V DD

CE PM1

0.1 μ F

SCK0

SCK

SDO MISO0

SDI MOSI0

GND

Figure 10.16 ■ Circuit connection between the TC72 and the HCS12

void openspi0(void)
{
SPI0BR 5 0x10;

// set baud rate to 6 MHz

SPI0CR1 5 0x50;
SPI0CR2 5 0x02;
WOMS 5 0x00; // enable Port S pull-up

}
void int2alpha(unsigned int xx, char *ptr) {
int quo;
*(ptr 1 2) 5 xx % 10 1 0x30;
quo 5 xx/10;
if(quo ! 5 0){
*(ptr 1 1) 5 quo % 10 1 0x30;
quo 5 quo/10; // tens digit

}
if(quo ! 5 0)
*ptr 5 quo 1 0x30;
}
void read_temp (char *ptr)
{

char hi_byte, lo_byte, temp, *bptr;

unsigned int result;

*ptr 5 0x20; // initialize the temperature buffer to 0.0

*(ptr 1 1) 5 0x20; // and place two space characters before

*(ptr 1 2) 5 0x30; // 0.0

*(ptr 1 3) 5 '.'; // “

*(ptr 1 4) 5 0x30; // “

bptr 5 ptr;

PTM | 5 BIT1; // enable TC72 data transfer

putcspi0 (0x80); // send out TC72 control register write address

putcspi0 (0x11); // perform one-shot conversion

PTM & 5 , BIT1; // disable TC72 data transfer

delayby100ms(2); // wait until temperature conversion is complete