FreeCalypso > hg > freecalypso-tools
changeset 77:0f11da299b7d
buzplayer: beginning of timer implementation
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Thu, 27 Oct 2016 04:01:16 +0000 |
parents | 5bbba2cab6f3 |
children | e3d40f49d8c4 |
files | target-utils/buzplayer/Makefile target-utils/buzplayer/main.c target-utils/buzplayer/timer.c target-utils/include/timer.h |
diffstat | 4 files changed, 79 insertions(+), 1 deletions(-) [+] |
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--- a/target-utils/buzplayer/Makefile Thu Oct 27 03:50:40 2016 +0000 +++ b/target-utils/buzplayer/Makefile Thu Oct 27 04:01:16 2016 +0000 @@ -7,7 +7,7 @@ INSTDIR=/opt/freecalypso/target-bin PROG= buzplayer -OBJS= crt0.o cmdtab.o main.o mygetchar.o +OBJS= crt0.o cmdtab.o main.o mygetchar.o timer.o LIBS= ../libcommon/libcommon.a ../libprintf/libprintf.a ../libbase/libbase.a LDS= ../env/iram.lds
--- a/target-utils/buzplayer/main.c Thu Oct 27 03:50:40 2016 +0000 +++ b/target-utils/buzplayer/main.c Thu Oct 27 04:01:16 2016 +0000 @@ -6,6 +6,7 @@ printf("FreeCalypso buzzer player running\n"); print_boot_rom_info(); *(volatile u16 *)0xfffe4806 = 0xFFF3; /* enable ARMIO clock */ + timer_init(); for (;;) { putchar('='); if (command_entry())
--- /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; +}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/target-utils/include/timer.h Thu Oct 27 04:01:16 2016 +0000 @@ -0,0 +1,58 @@ +/* + * Definitions for Calypso general-purpose timer registers + * + * This header is usable from both .c and .S source files. + */ + +#ifndef _CALYPSO_TIMER_H +#define _CALYPSO_TIMER_H + +#define TIMER1_BASE_ADDR 0xFFFE3800 +#define TIMER2_BASE_ADDR 0xFFFE6800 + +#ifdef __ASSEMBLER__ + +/* + * Assembly source with cpp + * + * The most convenient way to access registers like these from ARM + * assembly is to load the base address of the register block in some + * ARM register, using only one ldr rN, =xxx instruction and only one + * literal pool entry, and then access various registers in the block + * from the same base using the immediate offset addressing mode. + * + * Here we define the offsets for the usage scenario above. + */ + +#define CNTL_TIM 0x00 +#define LOAD_TIM 0x02 +#define READ_TIM 0x04 + +#else + +/* + * C source + * + * For access from C, we define the layout of each timer register block + * as a struct, and then define a pleudo-global-var for easy "volatile" + * access to each of the 2 timers. + */ + +struct timer_regs { + unsigned char cntl; + unsigned char pad; + unsigned short load; + unsigned short read; +}; + +#define TIMER1_REGS (*(volatile struct timer_regs *) TIMER1_BASE_ADDR) +#define TIMER2_REGS (*(volatile struct timer_regs *) TIMER2_BASE_ADDR) + +#endif + +/* CNTL register bit definitions */ +#define CNTL_START 0x01 +#define CNTL_AUTO_RELOAD 0x02 +#define CNTL_CLOCK_ENABLE 0x20 + +#endif /* include guard */