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rp/clocks: fix comments and rosc defaults

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if rosc really does run at 140MHz in high at div=1 then these values
were not correct and would've exceeded the chip spec. the HIL test
device seems to run fast (150MHz) so they're still not quite correct,
but rosc has high variance anyway so it's probably fine.
This commit is contained in:
pennae 2023-05-13 19:14:27 +02:00
parent 1379eb4e70
commit 0d4ab559a7
1 changed files with 9 additions and 7 deletions
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16
embassy-rp/src/clocks.rs
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@ -64,16 +64,19 @@ impl ClockConfig {
div_frac: 0, div_frac: 0,
}, },
peri_clk_src: Some(PeriClkSrc::Sys), peri_clk_src: Some(PeriClkSrc::Sys),
// CLK USB = PLL USB (48MHz) / 1 = 48MHz
usb_clk: Some(UsbClkConfig { usb_clk: Some(UsbClkConfig {
src: UsbClkSrc::PllUsb, src: UsbClkSrc::PllUsb,
div: 1, div: 1,
phase: 0, phase: 0,
}), }),
// CLK ADC = PLL USB (48MHZ) / 1 = 48MHz
adc_clk: Some(AdcClkConfig { adc_clk: Some(AdcClkConfig {
src: AdcClkSrc::PllUsb, src: AdcClkSrc::PllUsb,
div: 1, div: 1,
phase: 0, phase: 0,
}), }),
// CLK RTC = PLL USB (48MHz) / 1024 = 46875Hz
rtc_clk: Some(RtcClkConfig { rtc_clk: Some(RtcClkConfig {
src: RtcClkSrc::PllUsb, src: RtcClkSrc::PllUsb,
div_int: 1024, div_int: 1024,
@ -102,15 +105,17 @@ impl ClockConfig {
}, },
peri_clk_src: Some(PeriClkSrc::Rosc), peri_clk_src: Some(PeriClkSrc::Rosc),
usb_clk: None, usb_clk: None,
// CLK ADC = ROSC (140MHz) / 3 ≅ 48MHz
adc_clk: Some(AdcClkConfig { adc_clk: Some(AdcClkConfig {
src: AdcClkSrc::Rosc, src: AdcClkSrc::Rosc,
div: 1, div: 3,
phase: 0, phase: 0,
}), }),
// CLK RTC = ROSC (140MHz) / 2986.667969 ≅ 46875Hz
rtc_clk: Some(RtcClkConfig { rtc_clk: Some(RtcClkConfig {
src: RtcClkSrc::Rosc, src: RtcClkSrc::Rosc,
div_int: 1024, div_int: 2986,
div_frac: 0, div_frac: 171,
phase: 0, phase: 0,
}), }),
} }
@ -362,7 +367,6 @@ pub(crate) unsafe fn init(config: ClockConfig) {
} }
if let Some(conf) = config.usb_clk { if let Some(conf) = config.usb_clk {
// CLK USB = PLL USB (48MHz) / 1 = 48MHz
c.clk_usb_div().write(|w| w.set_int(conf.div)); c.clk_usb_div().write(|w| w.set_int(conf.div));
c.clk_usb_ctrl().write(|w| { c.clk_usb_ctrl().write(|w| {
w.set_phase(conf.phase); w.set_phase(conf.phase);
@ -374,7 +378,6 @@ pub(crate) unsafe fn init(config: ClockConfig) {
} }
if let Some(conf) = config.adc_clk { if let Some(conf) = config.adc_clk {
// CLK ADC = PLL USB (48MHZ) / 1 = 48MHz
c.clk_adc_div().write(|w| w.set_int(conf.div)); c.clk_adc_div().write(|w| w.set_int(conf.div));
c.clk_adc_ctrl().write(|w| { c.clk_adc_ctrl().write(|w| {
w.set_phase(conf.phase); w.set_phase(conf.phase);
@ -386,7 +389,6 @@ pub(crate) unsafe fn init(config: ClockConfig) {
} }
if let Some(conf) = config.rtc_clk { if let Some(conf) = config.rtc_clk {
// CLK RTC = PLL USB (48MHz) / 1024 = 46875Hz
c.clk_rtc_ctrl().modify(|w| { c.clk_rtc_ctrl().modify(|w| {
w.set_enable(false); w.set_enable(false);
}); });
@ -661,7 +663,7 @@ unsafe fn configure_pll(p: pac::pll::Pll, input_freq: u32, config: PllConfig) {
// Wait for PLL to lock // Wait for PLL to lock
while !p.cs().read().lock() {} while !p.cs().read().lock() {}
// Wait for PLL to lock // Set post-dividers
p.prim().write(|w| { p.prim().write(|w| {
w.set_postdiv1(config.post_div1); w.set_postdiv1(config.post_div1);
w.set_postdiv2(config.post_div2); w.set_postdiv2(config.post_div2);