AOpen DEX4500 series Assembly Manual page 48

2. Stop Timer
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x07);
outportb(0x2F,0x08);
outportb(0x2E,0xF6);
outportb(0x2F,byBit);
outportb(0x2E,0xAA);
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x07);
outportb(0x2F,0x08);
outportb(0x2E,0x30);
outportb(0x2F,byBit);
outportb(0x2E,0xAA);
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x07);
outportb(0x2F,0x08);
outportb(0x2E,0xF7);
outportb(0x2F,byBit);
outportb(0x2E,0xAA);
47
3. Set Min/Sec Mode
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x07);
outportb(0x2F,0x08);
outportb(0x2E,0xF5);
outportb(0x2F,byBit);
outportb(0x2E,0xAA);
4. Start Timer
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x07);
outportb(0x2F,0x08);
outportb(0x2E,0xF6);
outportb(0x2F,byBit);
outportb(0x2E,0xAA);