/**
* \brief This function will change the clock source of the AST module.
*
* \param ast Base address of the AST (i.e. &AVR32_AST).
* \param osc_type The oscillator you want to use. If you need a better
* accuracy, use the 32 KHz oscillator (i.e. AST_OSC_32KHZ).
* \param psel The preselector value for the corresponding oscillator (4-bits).
* To obtain this value, you can use this formula:
* psel = log(Fosc/Fast)/log(2)-1, where Fosc is the frequency of the
* oscillator you are using (32 KHz or 115 KHz) and Fast the frequency
* desired.
*
* \return Boolean true if the initialization succeeds, false otherwise.
*/
bool ast_change_clk_source(volatile avr32_ast_t *ast, uint8_t osc_type,
uint8_t psel)
{
uint32_t time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
/* Disable the clock */
ast->clock &= ~(AVR32_AST_CLOCK_CEN_MASK);
time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
/* Change the clock source */
ast->clock = osc_type << AVR32_AST_CLOCK_CSSEL_OFFSET;
time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
/* Enable the clock again */
ast->clock |= AVR32_AST_CLOCK_CEN_MASK;
time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
/* Set the new prescalar value */
ast->cr = psel << AVR32_AST_CR_PSEL_OFFSET;
/* Wait until the ast CTRL register is up-to-date */
while (ast_is_busy(ast)) {
}
return true;
}
/**
* \brief This function will initialize the AST module in counter Mode.
*
* \note If you use the 32 KHz oscillator, it must be enabled before calling
* this function.
*
* \param ast Base address of the AST (i.e. &AVR32_AST).
* \param osc_type The oscillator you want to use. If you need a better
* accuracy, use the 32 KHz oscillator (i.e. AST_OSC_32KHZ).
* \param psel The preselector value for the corresponding oscillator (4-bits).
* To obtain this value, you can use this formula:
* psel = log(Fosc/Fast)/log(2)-1, where Fosc is the frequency of the
* oscillator you are using (32 KHz or 115 KHz) and Fast the frequency
* desired.
* \param ast_counter Startup counter value
*
* \return Boolean true if the initialization succeeds, false otherwise.
*/
bool ast_init_counter(volatile avr32_ast_t *ast, uint8_t osc_type,
uint8_t psel, uint32_t ast_counter)
{
uint32_t time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
ast->clock = osc_type << AVR32_AST_CLOCK_CSSEL_OFFSET;
time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
ast->clock |= AVR32_AST_CLOCK_CEN_MASK;
time_out = AST_POLL_TIMEOUT;
while (ast_is_clkbusy(ast)) {
if (--time_out == 0) {
return false;
}
}
/* Set the new AST configuration */
ast->cr = (AST_MODE_COUNTER << AVR32_AST_CR_CAL_OFFSET) |
(psel << AVR32_AST_CR_PSEL_OFFSET);
/* Wait until the ast CTRL register is up-to-date */
while (ast_is_busy(ast)) {
}
/* Set the calendar */
ast_set_counter_value(ast, ast_counter);
return true;
}
int ast_init_calendar(volatile avr32_ast_t *ast,
unsigned char osc_type,
unsigned char psel,
ast_calendar_t ast_calendar)
{
while (ast_is_clkbusy(ast));
ast->clock = AVR32_AST_CLOCK_CEN_MASK |
osc_type << AVR32_AST_CLOCK_CSSEL_OFFSET;
// Set the new AST configuration
ast->cr = AST_MODE_CALENDAR << AVR32_AST_CR_CAL_OFFSET |
psel << AVR32_AST_CR_PSEL_OFFSET ;
// Wait until the ast CTRL register is up-to-date
while (ast_is_busy(ast));
// Set the calendar
ast_set_calendar_value(ast, ast_calendar);
return 1;
}