Page 178 - Programming Microcontrollers in C

Microcontroller Memory 163

void program(int,int );
void erase(int );

0101 0101 00FF int EEPROM[0xff] @0x101;

void program(int address, int value)
0050 0051 {
0801 BF 50 STX $50
0803 B7 51 STA $51
0805 12 07 BSET 1,$07 EEPROM_CTL.E1LAT=1;
0807 D7 01 01 STA $0101,X EEPROM[address]=value;
080A 10 07 BSET 0,$07 EEPROM_CTL.E1PGM=1;
080C 5F CLRX delay(PROG_TIME);
080D A6 0A LDA #$0A
080F CD 00 00 JSR $****
0812 13 07 BCLR 1,$07 EEPROM_CTL.E1LAT=0;

0814 81 RTS }

void erase(int x)
0052 {
0815 B7 52 STA $52
0817 12 07 BSET 1,$07 EEPROM_CTL.E1LAT=1;
0819 14 07 BSET 2,$07 EEPROM_CTL.E1ERA=1;
081B 97 TAX EEPROM[x]=0;
081C 4F CLRA
081D D7 01 01 STA $0101,X
0820 10 07 BSET 0,$07 EEPROM_CTL.E1PGM=1;
0822 5F CLRX delay(PROG_TIME);
0823 A6 0A LDA #$0A
0825 CD 00 00 JSR $****
0828 13 07 BCLR 1,$07 EEPROM_CTL.E1LAT=0;

082A 81 RTS }

The function program() requires 20 bytes and the function
erase requires 22. This is a good point to explore some of the C
programming practices that can lead to poor M68HC05 family com­