The SPI Function - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 520

Example 10.11
▼

For the circuit shown in Figure 10.30, write a program to display the following message and
shift the information from right to left every second and enable blinking:
08:30:40 Wednesday, 72°F, humidity: 60%

Solution: We use plane P0 to shift the message once every half a second. The message in plane
P0 is used to multiplex the display in half a second and the message sent to plane P1 is used to
multiplex the display in the next half of a second. We display the space character in each matrix
display using plane P1 and display the normal characters using plane P0. A delay function is
invoked once every second to shift the message to plane P0. The program is as follows:
#include “c:\cwHCS12\include\hcs12.h”
#include “c:\cwHCS12\include\spi0util.h”
#include “c:\cwHCS12\include\delay.h”
void send2max (char x1, char x2, char x3, char x4);
void openspi0 (void);
char msgP0[41] 5 “08:30:40 Wednesday, 72°F, humidity: 60% “;

void main (void)
{

char i1, i2, i3, i4;

char j1, j2, j3, j4;

char k;

openspi0();

DDRM | 5 BIT5; // configure PM5 pin for output

send2max(0x01, 0xFF, 0x01, 0xFF);

send2max(0x02, 0xFF, 0x02, 0xFF);

send2max(0x03, 0x01, 0x03, 0x01);

send2max(0x04, 0x1D, 0x04, 0x1D); // configuration register

send2max(0x40, 0x20, 0x40, 0x20); // send space character to plane P1

send2max(0x41, 0x20, 0x41, 0x20);

send2max(0x42, 0x20, 0x42, 0x20);

send2max(0x43, 0x20, 0x43, 0x20);

k 5 0;

while (1) {

i1 5 k;

i2 5 (k 1 1)%40;

i3 5 (k 1 2)%40;

i4 5 (k 1 3)%40;

j1 5 (k 1 4)%40;

j2 5 (k 1 5)%40;

j3 5 (k 1 6)%40;

j4 5 (k 1 7)%40;

sendtomax(0x20, msgP0[i1], 0x20, msgP0[j1]);

sendtomax(0x21, msgP0[i2], 0x21, msgP0[j2]);

sendtomax(0x22, msgP0[i3], 0x22, msgP0[j3]);

sendtomax(0x23, msgP0[i4], 0x23, msgP0[j4]);

delayby100ms(10); /* wait for 1 s */

k 5 (k 1 1)%40;

}

}