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PIT ports and modes

This commit is contained in:
Dan Luu 2013-03-23 00:31:14 -04:00
parent 1b7be5151d
commit 9e6e4485d5
1 changed files with 9 additions and 0 deletions
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9
PIT.js
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@ -15,6 +15,9 @@ function PIT(PC, ah, bh) {
}
this.speaker_data_on = 0;
this.set_irq = ah;
// Ports:
// 0x40: Channel 0 data port
// 0x61: Control
PC.register_ioport_write(0x40, 4, 1, this.ioport_write.bind(this));
PC.register_ioport_read(0x40, 3, 1, this.ioport_read.bind(this));
PC.register_ioport_read(0x61, 1, 1, this.speaker_ioport_read.bind(this));
@ -58,22 +61,28 @@ IRQCH.prototype.pit_get_out = function() {
d = this.get_time() - this.count_load_time;
switch (this.mode) {
default:
// Interrupt on terminal count
case 0:
eh = (d >= this.count) >> 0;
break;
// One shot
case 1:
eh = (d < this.count) >> 0;
break;
// Frequency divider
case 2:
if ((d % this.count) == 0 && d != 0)
eh = 1;
else
eh = 0;
break;
// Square wave
case 3:
eh = ((d % this.count) < (this.count >> 1)) >> 0;
break;
// SW strobe
case 4:
// HW strobe
case 5:
eh = (d == this.count) >> 0;
break;