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LPC1768: Enable usticker 

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>
pull/7009/head
Mahesh Mahadevan 2018-05-17 12:19:14 -05:00 committed by Bartek Szatkowski
parent c18763bb41
commit 870600400d
1 changed files with 22 additions and 12 deletions
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34
targets/TARGET_NXP/TARGET_LPC176X/us_ticker.c
View File

@ -17,34 +17,44 @@
#include "us_ticker_api.h"
#include "PeripheralNames.h"
const ticker_info_t* us_ticker_get_info()
{
static const ticker_info_t info = {
1000000, // 1 MHz
32 // 32 bit counter
};
return &info;
}
static bool us_ticker_inited = false;
#define US_TICKER_TIMER ((LPC_TIM_TypeDef *)LPC_TIM3_BASE)
#define US_TICKER_TIMER_IRQn TIMER3_IRQn
int us_ticker_inited = 0;
void us_ticker_init(void) {
if (us_ticker_inited) return;
us_ticker_inited = 1;
if (us_ticker_inited) {
/* calling init again should cancel current interrupt */
us_ticker_disable_interrupt();
return;
}
us_ticker_inited = true;
LPC_SC->PCONP |= 1 << 23; // Clock TIMER_3
US_TICKER_TIMER->CTCR = 0x0; // timer mode
uint32_t PCLK = SystemCoreClock / 4;
US_TICKER_TIMER->TCR = 0x2; // reset
uint32_t prescale = PCLK / 1000000; // default to 1MHz (1 us ticks)
US_TICKER_TIMER->PR = prescale - 1;
US_TICKER_TIMER->TCR = 1; // enable = 1, reset = 0
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 US_TICKER_TIMER->TC;
}