christoph/lecture-operating-system-development
1
Fork 0
Code Activity

implement pcspk

Browse Source
This commit is contained in:
churl
2022-04-24 13:09:49 +02:00
parent f44e7d3956
commit 3d3dd4dd2e
1 changed files with 24 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
c_os/devices/PCSPK.cc
View File

@ -89,6 +89,30 @@ inline void PCSPK::delay (int time) {
/* Hier muess Code eingefuegt werden */
// 1.19 MHz => 1s for full countdown
unsigned short cntStart = 1193180 / 1000; // 1s / 1000 = 1ms countdown
// 00110000 => 0x30: Counter0, LoByte/HiByte, Mode0, Binary
// 00110010 => 0x32: Counter0, LoByte/HiByte, Mode1, Binary
// 00110100 => 0x34: Counter0, LoByte/HiByte, Mode2, Binary
// 00110110 => 0x36: Counter0, LoByte/HiByte, Mode3, Binary
control.outb(0x34); // Zaehler-0 konfigurieren
data0.outb(cntStart & 0xFF); // Zaehler-0 laden (Lobyte)
data0.outb(cntStart >> 8); // Zaehler-0 laden (Hibyte)
int initial_count, current_count;
for (int i = 0; i < time; ++i) {
initial_count = readCounter();
while(1) {
current_count = readCounter();
if (current_count > initial_count) break; // The counter has already been reset
initial_count = current_count;
}
}
}