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sam3x: Add convenince functions for setting clocks and usart baudrate.

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Gareth McMullin 2013-05-03 14:08:18 -07:00 committed by Piotr Esden-Tempski
parent 8265953b35
commit e2eadfddb8
4 changed files with 30 additions and 0 deletions
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4
include/libopencm3/sam3x/pmc.h
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@ -125,6 +125,8 @@
#define PMC_SR_LOCKA (0x01 << 1) #define PMC_SR_LOCKA (0x01 << 1)
#define PMC_SR_MOSCXTS (0x01 << 0) #define PMC_SR_MOSCXTS (0x01 << 0)
extern u32 pmc_mck_frequency;
enum mck_src { enum mck_src {
MCK_SRC_SLOW = 0, MCK_SRC_SLOW = 0,
MCK_SRC_MAIN = 1, MCK_SRC_MAIN = 1,
@ -137,5 +139,7 @@ void pmc_xtal_enable(bool en, u8 startup_time);
void pmc_plla_config(u8 mul, u8 div); void pmc_plla_config(u8 mul, u8 div);
void pmc_peripheral_clock_enable(u8 pid); void pmc_peripheral_clock_enable(u8 pid);
void pmc_peripheral_clock_disable(u8 pid); void pmc_peripheral_clock_disable(u8 pid);
void pmc_clock_setup_in_xtal_12mhz_out_84mhz(void);
#endif #endif

1
include/libopencm3/sam3x/usart.h
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@ -196,6 +196,7 @@ enum usart_flowcontrol {
USART_FLOWCONTROL_RTS_CTS, USART_FLOWCONTROL_RTS_CTS,
}; };
void usart_set_baudrate(u32 usart, u32 baud);
void usart_set_databits(u32 usart, int bits); void usart_set_databits(u32 usart, int bits);
void usart_set_stopbits(u32 usart, enum usart_stopbits); void usart_set_stopbits(u32 usart, enum usart_stopbits);
void usart_set_parity(u32 usart, enum usart_parity); void usart_set_parity(u32 usart, enum usart_parity);

19
lib/sam3x/pmc.c
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@ -18,6 +18,10 @@
*/ */
#include <libopencm3/sam3x/pmc.h> #include <libopencm3/sam3x/pmc.h>
#include <libopencm3/sam3x/eefc.h>
/** Default peripheral clock frequency after reset. */
u32 pmc_mck_frequency = 4000000;
void pmc_xtal_enable(bool en, u8 startup_time) void pmc_xtal_enable(bool en, u8 startup_time)
{ {
@ -60,3 +64,18 @@ void pmc_mck_set_source(enum mck_src src)
while (!(PMC_SR & PMC_SR_MCKRDY)); while (!(PMC_SR & PMC_SR_MCKRDY));
} }
void pmc_clock_setup_in_xtal_12mhz_out_84mhz(void)
{
eefc_set_latency(4);
/* 12MHz external xtal, maximum possible startup time */
pmc_xtal_enable(true, 0xff);
/* Select as main oscillator */
CKGR_MOR |= CKGR_MOR_KEY | CKGR_MOR_MOSCSEL;
/* Multiply by 7 for 84MHz */
pmc_plla_config(7, 1);
pmc_mck_set_source(MCK_SRC_PLLA);
pmc_mck_frequency = 84000000;
}

6
lib/sam3x/usart.c
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@ -18,6 +18,12 @@
*/ */
#include <libopencm3/sam3x/usart.h> #include <libopencm3/sam3x/usart.h>
#include <libopencm3/sam3x/pmc.h>
void usart_set_baudrate(u32 usart, u32 baud)
{
USART_BRGR(usart) = pmc_mck_frequency / (16 * baud);
}
void usart_set_databits(u32 usart, int bits) void usart_set_databits(u32 usart, int bits)
{ {