FreeCalypso > hg > freecalypso-tools
diff target-utils/buzplayer/timer.c @ 77:0f11da299b7d
buzplayer: beginning of timer implementation
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Thu, 27 Oct 2016 04:01:16 +0000 |
parents | |
children | e3d40f49d8c4 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/target-utils/buzplayer/timer.c Thu Oct 27 04:01:16 2016 +0000 @@ -0,0 +1,19 @@ +/* + * FreeCalypso buzzer "melodies" have times measured in TDMA frames, + * as that is the time unit in the main firmware which will ultimately + * play them. In this standalone buzzer player we simulate TDMA frame + * timing by programming Calypso TIMER1 with the period of 1875, and + * we detect timer overflow (one virtual TDMA frame time having passed) + * by polling the read register to avoid the need for interrupt handling + * infrastructure. + */ + +#include "types.h" +#include "timer.h" + +timer_init() +{ + TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE; + TIMER1_REGS.load = 1875; + TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE | CNTL_AUTO_RELOAD | CNTL_START; +}