Diff: Cortex-M3/Bit-banding/bitband.c

Revision:

0:bf7b9fba3924

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Cortex-M3/Bit-banding/bitband.c	Sun Mar 20 05:38:56 2011 +0000
@@ -0,0 +1,209 @@
+/***********************************************************************//**
+ * @file		bitband.c
+ * @purpose		This example used to test bit-banding feature of Cortex-M3
+ * 				processor.
+ * @version		2.0
+ * @date		21. May. 2010
+ * @author		NXP MCU SW Application Team
+ *---------------------------------------------------------------------
+ * Software that is described herein is for illustrative purposes only
+ * which provides customers with programming information regarding the
+ * products. This software is supplied "AS IS" without any warranties.
+ * NXP Semiconductors assumes no responsibility or liability for the
+ * use of the software, conveys no license or title under any patent,
+ * copyright, or mask work right to the product. NXP Semiconductors
+ * reserves the right to make changes in the software without
+ * notification. NXP Semiconductors also make no representation or
+ * warranty that such application will be suitable for the specified
+ * use without further testing or modification.
+ **********************************************************************/
+#include "lpc17xx_libcfg.h"
+#include "debug_frmwrk.h"
+
+/* Example group ----------------------------------------------------------- */
+/** @defgroup Cortex_M3_Bit_banding	Bit-banding
+ * @ingroup Cortex_M3_Examples
+ * @{
+ */
+
+/************************** PRIVATE DEFINTIONS*************************/
+/* The processor memory map includes two bit-band regions. These occupy the lowest
+ * 1MB of the SRAM and peripheral memory regions respectively.
+ * + SRAM: 	Bit-band region: 	0x20000000 - 0x20100000
+ * 			Bit-band alias:		0x22000000 - 0x23FFFFFF
+ * + PERI:	Bit-band region:	0x40000000 - 0x40100000
+ * 			Bit-band alias:		0x42000000 - 0x43FFFFFF
+ * The mapping formula:
+ * 		bit_word_offset = (byte_offset * 32) + (bit_number * 4)
+ * 		bit_word_address = bit_band_base + bit_word_offset
+ * where:
+ * 	+ bit_word_offset: the position of the target bit in the bit-band memory region
+ * 	+ bit_word_addr: the address of the word in the alias memory region that maps to the target bit
+ *  + bit_band_base: the starting address of the alias region
+ *  + byte_offset: the number of byte in the bit-band region that contains the targeted bit
+ *  + bit_number: is the bit position (0-7) of the targeted bit
+ *
+ * Note: The fact, the SRAM on LPC1768 just available in two ranges:
+ * 	+ 0x2007C000 - 0x2007FFFF: for SRAM - bank 0
+ *  + 0x20080000 - 0x20083FFF: for SRAM - bank 1
+ *  (And one range for GPIO peripheral but assigned in SRAM ranges: 0x2009C000 - 0x2009FFFF)
+ */
+
+/* Bit band SRAM definitions */
+#define BITBAND_SRAM_REF   0x20000000
+#define BITBAND_SRAM_BASE  0x22000000
+
+#define BITBAND_SRAM(a,b) ((BITBAND_SRAM_BASE + ((a-BITBAND_SRAM_REF)<<5) + (b<<2)))  // Convert SRAM address
+
+/* Bit band PERIPHERAL definitions */
+#define BITBAND_PERI_REF   0x40000000
+#define BITBAND_PERI_BASE  0x42000000
+
+#define BITBAND_PERI(a,b) ((BITBAND_PERI_BASE + ((a-BITBAND_PERI_REF)<<5) + (b<<2)))  // Convert PERI address
+
+/* Basic bit band function definitions */
+#define BITBAND_SRAM_ClearBit(a,b)	(*(volatile uint32_t *) (BITBAND_SRAM(a,b)) = 0)
+#define BITBAND_SRAM_SetBit(a,b)	(*(volatile uint32_t *) (BITBAND_SRAM(a,b)) = 1)
+#define BITBAND_SRAM_GetBit(a,b)	(*(volatile uint32_t *) (BITBAND_SRAM(a,b)))
+
+#define BITBAND_PERI_ClearBit(a,b)	(*(volatile uint32_t *) (BITBAND_PERI(a,b)) = 0)
+#define BITBAND_PERI_SetBit(a,b)	(*(volatile uint32_t *) (BITBAND_PERI(a,b)) = 1)
+#define BITBAND_PERI_GetBit(a,b)	(*(volatile uint32_t *) (BITBAND_PERI(a,b)))
+
+/* Variable address in SRAM
+ * should be in one of two range:
+ * 	+ 0x2007C000 - 0x20083FFF: for SRAM
+ *  + 0x20080000 - 0x20083FFF: for GPIO
+ */
+#define VAR_ADDRESS		0x2007C000
+#define VAR_BIT			3 //Bit 3
+
+/* Peripheral address
+ * should be in range: 0x40000000 - 0x40100000
+ */
+#define PERI_ADDRESS	0x40020000 // SPI Control Register (S0SPCR)
+#define PERI_BIT		5 //bit 5 - Master mode select
+
+/************************** PRIVATE VARIABLES *************************/
+uint8_t menu[]=
+	"********************************************************************************\n\r"
+	"Hello NXP Semiconductors \n\r"
+	"Bit-banding demo \n\r"
+	"\t - MCU: LPC17xx \n\r"
+	"\t - Core: ARM CORTEX-M3 \n\r"
+	"\t - Communicate via: UART0 - 115200 bps \n\r"
+	"This example used to test Bit-banding feature of Cortex-M3 processor\n\r"
+	"********************************************************************************\n\r";
+
+/*-------------------------MAIN FUNCTION------------------------------*/
+/*********************************************************************//**
+ * @brief		c_entry: main function
+ * @param[in]	none
+ * @return 		int
+ **********************************************************************/
+int c_entry(void) { /* Main Program */
+
+	uint32_t temp;
+
+	/* Initialize debug via UART0
+	 * – 115200bps
+	 * – 8 data bit
+	 * – No parity
+	 * – 1 stop bit
+	 * – No flow control
+	 */
+	debug_frmwrk_init();
+	//print menu
+	_DBG(menu);
+
+	/* test Bit-banding SRAM first --------------------------------------------------------- */
+	_DBG_("Test bit-band SRAM... ");
+
+	//read variable at VAR_ADDRESS
+	temp = (*(volatile uint32_t *)(VAR_ADDRESS));
+	//print temp value
+	_DBG("The value at address "); _DBH32(VAR_ADDRESS); _DBG(": ");
+	_DBH32(temp); _DBG_("");
+
+	/* Use bitband function to read VAR_BIT value */
+	temp = BITBAND_SRAM_GetBit(VAR_ADDRESS,VAR_BIT);
+	_DBG("Use bit-band function to get value at bit 3: ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+
+	/* clear bit */
+	BITBAND_SRAM_ClearBit(VAR_ADDRESS,VAR_BIT);
+	/* re-read temp value */
+	temp = (*(volatile uint32_t *)(VAR_ADDRESS));
+	_DBG("Value after clear bit 3 value by using bit-band function: ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+
+	/* Set bit */
+	BITBAND_SRAM_SetBit(VAR_ADDRESS,VAR_BIT);
+	/* re-read temp value */
+	temp = (*(volatile uint32_t *)(VAR_ADDRESS));
+	_DBG("Value after set bit 3 value by using bit-band function: ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+	_DBG_("");
+
+	/* Then, test Bit-banding PERI --------------------------------------------------------- */
+	_DBG_("Test bit-band PERIPHERAL... ");
+
+	LPC_SPI->SPCR =(1<<5)|(1<<3)|(10<<8);
+
+	/* Read the current value of peripheral register */
+	temp = (*(volatile uint32_t *)(PERI_ADDRESS));
+	_DBG("The value of peripheral register at "); _DBH32(PERI_ADDRESS); _DBG(": ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+
+	/* Use bitband function to read VAR_BIT value */
+	temp = BITBAND_PERI_GetBit(PERI_ADDRESS,PERI_BIT);
+	_DBG("Use bit-band function to get value at bit 5: ");_DBG_(""); _DBH32(temp); _DBG_("");
+
+	/* clear bit */
+	BITBAND_PERI_ClearBit(PERI_ADDRESS,PERI_BIT);
+	/* re-read temp value */
+	temp = (*(volatile uint32_t *)(PERI_ADDRESS));
+	_DBG("Peripheral register after clear bit 5 value by using bit-band function: ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+
+	/* Set bit */
+	BITBAND_PERI_SetBit(PERI_ADDRESS,PERI_BIT);
+	/* re-read temp value */
+	temp = (*(volatile uint32_t *)(PERI_ADDRESS));
+	_DBG("Peripheral register after set bit 5 value by using bit-band function: ");_DBG_("");
+	_DBH32(temp); _DBG_("");
+
+	while (1);
+	return 0;
+}
+
+/* With ARM and GHS toolsets, the entry point is main() - this will
+ allow the linker to generate wrapper code to setup stacks, allocate
+ heap area, and initialize and copy code and data segments. For GNU
+ toolsets, the entry point is through __start() in the crt0_gnu.asm
+ file, and that startup code will setup stacks and data */
+int main(void) {
+	return c_entry();
+}
+
+#ifdef  DEBUG
+/*******************************************************************************
+ * @brief		Reports the name of the source file and the source line number
+ * 				where the CHECK_PARAM error has occurred.
+ * @param[in]	file Pointer to the source file name
+ * @param[in]    line assert_param error line source number
+ * @return		None
+ *******************************************************************************/
+void check_failed(uint8_t *file, uint32_t line) {
+	/* User can add his own implementation to report the file name and line number,
+	 ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
+
+	/* Infinite loop */
+	while (1)
+		;
+}
+#endif
+
+/*
+ * @}
+ */