djsundog
/
circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fix FrequencyIn for crystalless boards and simplify clock logic

This commit is contained in:
Dan Halbert 2021-12-06 22:34:43 -05:00
parent 92bb909bf0
commit 7e21344cf0
1 changed files with 37 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
ports/atmel-samd/common-hal/frequencyio/FrequencyIn.c
View File

@ -57,6 +57,11 @@ static frequencyio_frequencyin_obj_t *active_frequencyins[TC_INST_NUM];
volatile uint8_t reference_tc;
#ifdef SAM_D5X_E5X
static uint8_t dpll_gclk;
#if !BOARD_HAS_CRYSTAL
static uint8_t osculp32k_gclk;
#endif
#endif
void frequencyin_reset(void) {
@ -67,6 +72,11 @@ void frequencyin_reset(void) {
reference_tc = 0xff;
#ifdef SAM_D5X_E5X
dpll_gclk = 0xff;
#if !BOARD_HAS_CRYSTAL
osculp32k_gclk = 0xff;
#endif
#endif
}
@ -208,34 +218,38 @@ static bool frequencyin_samd51_start_dpll(void) {
return true;
}
uint8_t free_gclk = find_free_gclk(1);
if (free_gclk == 0xff) {
dpll_gclk = 0xff;
dpll_gclk = find_free_gclk(1);
if (dpll_gclk == 0xff) {
return false;
}
GCLK->PCHCTRL[OSCCTRL_GCLK_ID_FDPLL1].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(free_gclk);
// TC4-7 can only have a max of 100MHz source
// DPLL1 frequency equation with [X]OSC32K as source: 98.304MHz = 32768(2999 + 1 + 0/32)
// Will also enable the Lock Bypass due to low-frequency sources causing DPLL unlocks
// as outlined in the Errata (1.12.1)
OSCCTRL->Dpll[1].DPLLRATIO.reg = OSCCTRL_DPLLRATIO_LDRFRAC(0) | OSCCTRL_DPLLRATIO_LDR(2999);
#if BOARD_HAS_CRYSTAL
// we can use XOSC32K directly as the source
OSC32KCTRL->XOSC32K.bit.EN32K = 1;
OSCCTRL->Dpll[1].DPLLCTRLB.reg = OSCCTRL_DPLLCTRLB_REFCLK(1) | OSCCTRL_DPLLCTRLB_LBYPASS;
#else
// can't use OSCULP32K directly; need to setup a GCLK as a reference,
// which must be done in samd/clocks.c to avoid waiting for sync
return;
//OSC32KCTRL->OSCULP32K.bit.EN32K = 1;
//OSCCTRL->Dpll[1].DPLLCTRLB.reg = OSCCTRL_DPLLCTRLB_REFCLK(0);
#endif
OSCCTRL->Dpll[1].DPLLCTRLA.reg = OSCCTRL_DPLLCTRLA_ENABLE;
#if BOARD_HAS_CRYSTAL
// we can use XOSC32K directly as the source. It has already been initialized in clocks.c
OSCCTRL->Dpll[1].DPLLCTRLB.reg =
OSCCTRL_DPLLCTRLB_REFCLK(OSCCTRL_DPLLCTRLB_REFCLK_XOSC32_Val) | OSCCTRL_DPLLCTRLB_LBYPASS;
#else
// We can't use OSCULP32K directly. Set up a GCLK controlled by it
// Then use that GCLK as the reference oscillator for the DPLL.
osculp32k_gclk = find_free_gclk(1);
if (osculp32k_gclk == 0xff) {
return false;
}
enable_clock_generator(osculp32k_gclk, GCLK_GENCTRL_SRC_OSCULP32K_Val, 1);
GCLK->PCHCTRL[OSCCTRL_GCLK_ID_FDPLL1].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(OSCCTRL_GCLK_ID_FDPLL1);
OSCCTRL->Dpll[1].DPLLCTRLB.reg =
OSCCTRL_DPLLCTRLB_REFCLK(OSCCTRL_DPLLCTRLB_REFCLK_GCLK_Val) | OSCCTRL_DPLLCTRLB_LBYPASS;
#endif
OSCCTRL->Dpll[1].DPLLCTRLA.reg = OSCCTRL_DPLLCTRLA_ENABLE;
while (!(OSCCTRL->Dpll[1].DPLLSTATUS.bit.LOCK || OSCCTRL->Dpll[1].DPLLSTATUS.bit.CLKRDY)) {}
enable_clock_generator(free_gclk, GCLK_GENCTRL_SRC_DPLL1_Val, 1);
dpll_gclk = free_gclk;
enable_clock_generator(dpll_gclk, GCLK_GENCTRL_SRC_DPLL1_Val, 1);
return true;
}
@ -249,6 +263,11 @@ static void frequencyin_samd51_stop_dpll(void) {
dpll_gclk = 0xff;
}
if (osculp32k_gclk != 0xff) {
disable_clock_generator(osculp32k_gclk);
osculp32k_gclk = 0xff;
}
GCLK->PCHCTRL[OSCCTRL_GCLK_ID_FDPLL1].reg = 0;
OSCCTRL->Dpll[1].DPLLCTRLA.reg = 0;
OSCCTRL->Dpll[1].DPLLRATIO.reg = 0;