diff nuc-fw/nucleus/caltimer.h @ 79:947b1f473960

beginning of nuc-fw
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Sun, 11 Aug 2013 07:17:25 +0000
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nuc-fw/nucleus/caltimer.h	Sun Aug 11 07:17:25 2013 +0000
@@ -0,0 +1,59 @@
+/*
+ * Definitions for Calypso general-purpose timer registers
+ * Added to the FreeNucleus Calypso port by Spacefalcon the Outlaw.
+ *
+ * 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 */