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cc2538: sys_ctrl: Make it possible to use the 32-kHz crystal

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Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
This commit is contained in:
Benoît Thébaudeau 2013-11-04 21:34:53 +01:00
parent a6227e1e3e
commit 47d570343e
3 changed files with 46 additions and 5 deletions
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32
cpu/cc2538/dev/sys-ctrl.c
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@ -35,20 +35,39 @@
* \file
* Implementation of the cc2538 System Control driver
*/
#include "contiki.h"
#include "reg.h"
#include "cpu.h"
#include "dev/sys-ctrl.h"
#include "dev/gpio.h"
#include "dev/ioc.h"
#include <stdint.h>
#if SYS_CTRL_OSC32K_USE_XTAL
#define SYS_CTRL_OSCS 0
#else
#define SYS_CTRL_OSCS SYS_CTRL_CLOCK_CTRL_OSC32K
#endif
/*---------------------------------------------------------------------------*/
void
sys_ctrl_init()
{
uint32_t val;
#if SYS_CTRL_OSC32K_USE_XTAL
/* Set the XOSC32K_Q pads to analog for crystal */
GPIO_SOFTWARE_CONTROL(GPIO_PORT_TO_BASE(GPIO_D_NUM), GPIO_PIN_MASK(6));
GPIO_SET_INPUT(GPIO_PORT_TO_BASE(GPIO_D_NUM), GPIO_PIN_MASK(6));
ioc_set_over(GPIO_D_NUM, 6, IOC_OVERRIDE_ANA);
GPIO_SOFTWARE_CONTROL(GPIO_PORT_TO_BASE(GPIO_D_NUM), GPIO_PIN_MASK(7));
GPIO_SET_INPUT(GPIO_PORT_TO_BASE(GPIO_D_NUM), GPIO_PIN_MASK(7));
ioc_set_over(GPIO_D_NUM, 7, IOC_OVERRIDE_ANA);
#endif
/*
* Desired Clock Ctrl configuration:
* 32KHz source: RC
* 32KHz source: RC or crystal, according to SYS_CTRL_OSC32K_USE_XTAL
* System Clock: 32 MHz
* Power Down Unused
* I/O Div: 16MHz
@ -56,11 +75,18 @@ sys_ctrl_init()
* Rest: Don't care
*/
val = SYS_CTRL_CLOCK_CTRL_OSC32K | SYS_CTRL_CLOCK_CTRL_OSC_PD
val = SYS_CTRL_OSCS | SYS_CTRL_CLOCK_CTRL_OSC_PD
| SYS_CTRL_CLOCK_CTRL_IO_DIV_16MHZ | SYS_CTRL_CLOCK_CTRL_SYS_DIV_16MHZ;
REG(SYS_CTRL_CLOCK_CTRL) = val;
while((REG(SYS_CTRL_CLOCK_STA) & SYS_CTRL_CLOCK_STA_OSC) != 0);
while((REG(SYS_CTRL_CLOCK_STA) & (SYS_CTRL_CLOCK_STA_OSC32K |
SYS_CTRL_CLOCK_STA_OSC)) != SYS_CTRL_OSCS);
#if SYS_CTRL_OSC32K_USE_XTAL
/* Wait for the 32-kHz crystal oscillator to stabilize */
while(REG(SYS_CTRL_CLOCK_STA) & SYS_CTRL_CLOCK_STA_SYNC_32K);
while(!(REG(SYS_CTRL_CLOCK_STA) & SYS_CTRL_CLOCK_STA_SYNC_32K));
#endif
}
/*---------------------------------------------------------------------------*/
void