mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
vendor/NXP/LPC812/hal/us_ticker.c
- Committer:
- emilmont
- Date:
- 2013-06-14
- Revision:
- 10:3bc89ef62ce7
File content as of revision 10:3bc89ef62ce7:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <stddef.h> #include "us_ticker_api.h" #include "PeripheralNames.h" #define US_TICKER_TIMER_IRQn SCT_IRQn int us_ticker_inited = 0; void us_ticker_init(void) { if (us_ticker_inited) return; us_ticker_inited = 1; // Enable the SCT clock LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 8); // Clear peripheral reset the SCT: LPC_SYSCON->PRESETCTRL |= (1 << 8); // Unified counter (32 bits) LPC_SCT->CONFIG |= 1; // halt and clear the counter LPC_SCT->CTRL_L |= (1 << 2) | (1 << 3); // System Clock (12)MHz -> us_ticker (1)MHz LPC_SCT->CTRL_L |= ((SystemCoreClock/1000000 - 1) << 5); // unhalt the counter: // - clearing bit 2 of the CTRL register LPC_SCT->CTRL_L &= ~(1 << 2); NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler); NVIC_EnableIRQ(US_TICKER_TIMER_IRQn); } uint32_t us_ticker_read() { if (!us_ticker_inited) us_ticker_init(); return LPC_SCT->COUNT_U; } void us_ticker_set_interrupt(unsigned int timestamp) { // halt the counter: // - setting bit 2 of the CTRL register LPC_SCT->CTRL_L |= (1 << 2); // set timestamp in compare register LPC_SCT->MATCH[0].U = timestamp; // unhalt the counter: // - clearing bit 2 of the CTRL register LPC_SCT->CTRL_L &= ~(1 << 2); // if events are not enabled, enable them if (!(LPC_SCT->EVEN & 0x01)) { // comb mode = match only LPC_SCT->EVENT[0].CTRL = (1 << 12); // ref manual: // In simple applications that do not // use states, write 0x01 to this // register to enable an event LPC_SCT->EVENT[0].STATE |= 0x1; // enable events LPC_SCT->EVEN |= 0x1; } } void us_ticker_disable_interrupt(void) { LPC_SCT->EVEN &= ~1; } void us_ticker_clear_interrupt(void) { LPC_SCT->EVFLAG = 1; }