FreeCalypso > hg > freecalypso-tools
view 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 |
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children | e3d40f49d8c4 |
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/* * 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; }