FreeCalypso > hg > freecalypso-tools

comparison target-utils/buzplayer/timer.c @ 77:0f11da299b7d

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
buzplayer: beginning of timer implementation
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 27 Oct 2016 04:01:16 +0000
parents
children e3d40f49d8c4
comparison
equal deleted inserted replaced
76:5bbba2cab6f3 77:0f11da299b7d
1 /*
2 * FreeCalypso buzzer "melodies" have times measured in TDMA frames,
3 * as that is the time unit in the main firmware which will ultimately
4 * play them. In this standalone buzzer player we simulate TDMA frame
5 * timing by programming Calypso TIMER1 with the period of 1875, and
6 * we detect timer overflow (one virtual TDMA frame time having passed)
7 * by polling the read register to avoid the need for interrupt handling
8 * infrastructure.
9 */
10
11 #include "types.h"
12 #include "timer.h"
13
14 timer_init()
15 {
16 TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE;
17 TIMER1_REGS.load = 1875;
18 TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE | CNTL_AUTO_RELOAD | CNTL_START;
19 }