mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
Diff: targets/cmsis/TARGET_NXP/TARGET_LPC11UXX/cmsis_nvic.c
- Revision:
- 13:0645d8841f51
- Child:
- 15:4892fe388435
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/cmsis/TARGET_NXP/TARGET_LPC11UXX/cmsis_nvic.c Mon Aug 05 14:12:34 2013 +0300 @@ -0,0 +1,58 @@ +/* mbed Microcontroller Library - cmsis_nvic for LPC11U24 + * Copyright (c) 2011 ARM Limited. All rights reserved. + * + * CMSIS-style functionality to support dynamic vectors + */ + +#include "cmsis_nvic.h" + +/* In the M0, there is no VTOR. In the LPC range such as the LPC11U, + * whilst the vector table may only be something like 48 entries (192 bytes, 0xC0), + * the SYSMEMREMAP register actually remaps the memory from 0x10000000-0x100001FF + * to adress 0x0-0x1FF. In this case, RAM can be addressed at both 0x10000000 and 0x0 + * + * If we just copy the vectors to RAM and switch the SYSMEMMAP, any accesses to FLASH + * above the vector table before 0x200 will actually go to RAM. So we need to provide + * a solution where the compiler gets the right results based on the memory map + * + * Option 1 - We allocate and copy 0x200 of RAM rather than just the table + * - const data and instructions before 0x200 will be copied to and fetched/exec from RAM + * - RAM overhead: 0x200 - 0xC0 = 320 bytes, FLASH overhead: 0 + * + * Option 2 - We pad the flash to 0x200 to ensure the compiler doesn't allocate anything there + * - No flash accesses will go to ram, as there will be nothing there + * - RAM only needs to be allocated for the vectors, as all other ram addresses are normal + * - RAM overhead: 0, FLASH overhead: 320 bytes + * + * Option 2 is the one to go for, as RAM is the most valuable resource + */ + +#define NVIC_NUM_VECTORS (16 + 32) // CORE + MCU Peripherals +#define NVIC_RAM_VECTOR_ADDRESS (0x10000000) // Vectors positioned at start of RAM + +void NVIC_SetVector(IRQn_Type IRQn, uint32_t vector) { + int i; + // Space for dynamic vectors, initialised to allocate in R/W + static volatile uint32_t* vectors = (uint32_t*)NVIC_RAM_VECTOR_ADDRESS; + + // Copy and switch to dynamic vectors if first time called + if((LPC_SYSCON->SYSMEMREMAP & 0x3) != 0x1) { + uint32_t *old_vectors = (uint32_t *)0; // FLASH vectors are at 0x0 + for(i = 0; i < NVIC_NUM_VECTORS; i++) { + vectors[i] = old_vectors[i]; + } + LPC_SYSCON->SYSMEMREMAP = 0x1; // Remaps 0x0-0x1FF FLASH block to RAM block + } + + // Set the vector + vectors[IRQn + 16] = vector; +} + +uint32_t NVIC_GetVector(IRQn_Type IRQn) { + // We can always read vectors at 0x0, as the addresses are remapped + uint32_t *vectors = (uint32_t*)0; + + // Return the vector + return vectors[IRQn + 16]; +} +