Add RTC functions

teensy4/imxrt.h

 #define SNVS_HPLR			(IMXRT_SNVS.offset000)
 #define SNVS_HPCOMR			(IMXRT_SNVS.offset004)
 #define SNVS_HPCR			(IMXRT_SNVS.offset008)
-#define SNVS_HPSICR         (IMXRT_SNVS.offset00C)
-#define SNVS_HPSVCR         (IMXRT_SNVS.offset010)
+#define SNVS_HPSICR			(IMXRT_SNVS.offset00C)
+#define SNVS_HPSVCR			(IMXRT_SNVS.offset010)
 #define SNVS_HPSR			(IMXRT_SNVS.offset014)
-#define SNVS_HPSVSR         (IMXRT_SNVS.offset018)
-#define SNVS_HPHACIVR       (IMXRT_SNVS.offset01C)
-#define SNVS_HPHACR         (IMXRT_SNVS.offset020)
-#define SNVS_HPRTCMR		(IMXRT_SNVS.offset024)
-#define SNVS_HPRTCLR		(IMXRT_SNVS.offset028)
+#define SNVS_HPSVSR			(IMXRT_SNVS.offset018)
+#define SNVS_HPHACIVR			(IMXRT_SNVS.offset01C)
+#define SNVS_HPHACR			(IMXRT_SNVS.offset020)
+#define SNVS_HPRTCMR			(IMXRT_SNVS.offset024)
+#define SNVS_HPRTCLR			(IMXRT_SNVS.offset028)
 #define SNVS_HPTAMR			(IMXRT_SNVS.offset02C)
 #define SNVS_HPTALR			(IMXRT_SNVS.offset030)
 #define SNVS_LPLR			(IMXRT_SNVS.offset034)
 #define SNVS_LPCR			(IMXRT_SNVS.offset038)
-#define SNVS_LPMKCR         (IMXRT_SNVS.offset03C)
-#define SNVS_LPSVCR         (IMXRT_SNVS.offset040)
-#define SNVS_LPTDCR         (IMXRT_SNVS.offset048)
+#define SNVS_LPMKCR			(IMXRT_SNVS.offset03C)
+#define SNVS_LPSVCR			(IMXRT_SNVS.offset040)
+#define SNVS_LPTDCR			(IMXRT_SNVS.offset048)
 #define SNVS_LPSR			(IMXRT_SNVS.offset04C)
-#define SNVS_LPSRTCMR		(IMXRT_SNVS.offset050)
-#define SNVS_LPSRTCLR		(IMXRT_SNVS.offset054)
+#define SNVS_LPSRTCMR			(IMXRT_SNVS.offset050)
+#define SNVS_LPSRTCLR			(IMXRT_SNVS.offset054)
 #define SNVS_LPTAR			(IMXRT_SNVS.offset058)
-#define SNVS_LPSMCMR		(IMXRT_SNVS.offset05C)
-#define SNVS_LPSMCLR		(IMXRT_SNVS.offset060)
-#define SNVS_LPPGDR         (IMXRT_SNVS.offset064)
+#define SNVS_LPSMCMR			(IMXRT_SNVS.offset05C)
+#define SNVS_LPSMCLR			(IMXRT_SNVS.offset060)
+#define SNVS_LPPGDR			(IMXRT_SNVS.offset064)
 #define SNVS_LPGPR			(IMXRT_SNVS.offset068)
-#define IMXRT_SNVS_b	(*(IMXRT_REGISTER32_t *)0x400D4800)
+#define IMXRT_SNVS_b		(*(IMXRT_REGISTER32_t *)0x400D4800)
 #define SNVS_HPVIDR1			(IMXRT_SNVS_b.offset3F8)
 #define SNVS_HPVIDR2			(IMXRT_SNVS_b.offset3FC)
+#define SNVS_HPCR_BTN_MASK		((uint32_t)(1 << 27))
+#define SNVS_HPCR_BTN_CONFIG(n)		((uint32_t)(((n) & 0x07) << 24))
+#define SNVS_HPCR_HP_TS			((uint32_t)(1 << 16))
+#define SNVS_HPCR_HPCALB_VAL(n)		((uint32_t)(((n) & 0x1F) << 10))
+#define SNVS_HPCR_HPCALB_EN		((uint32_t)(1 << 8))
+#define SNVS_HPCR_PI_FREQ(n)		((uint32_t)(((n) & 0x0F) << 4))
+#define SNVS_HPCR_PI_EN			((uint32_t)(1 << 3))
+#define SNVS_HPCR_DIS_PI		((uint32_t)(1 << 2))
+#define SNVS_HPCR_HPTA_EN		((uint32_t)(1 << 1))
+#define SNVS_HPCR_RTC_EN		((uint32_t)(1 << 0))
 #define SNVS_DEFAULT_PGD_VALUE		(0x41736166U)
-#define SNVS_LPSR_PGD_MASK              (0x8)
-#define SNVS_LPCR_SRTC_ENV_MASK         (0x1)
-#define SNVS_LPCR_SRTC_ENV(x)           (((uint32_t)(((uint32_t)(x)) << 0)) & 0x1)
-#define SNVS_LPCR_LPTA_EN_MASK          (0x2)
-#define SNVS_LPCR_LPTA_EN(x)            (((uint32_t)(((uint32_t)(x)) << 1)) & 0x2)
-#define SNVS_LPCR_MC_ENV_MASK           (0x4)
-#define SNVS_LPCR_MC_ENV(x)             (((uint32_t)(((uint32_t)(x)) << 2)) & 0x4)
-#define SNVS_LPCR_LPWUI_EN_MASK         (0x8)
-#define SNVS_LPCR_LPWUI_EN(x)           (((uint32_t)(((uint32_t)(x)) << 3)) & 0x8)
-#define SNVS_LPCR_SRTC_INV_EN_MASK      (0x10)
-#define SNVS_LPCR_SRTC_INV_EN(x)        (((uint32_t)(((uint32_t)(x)) << 4)) & 0x10)
-#define SNVS_LPCR_DP_EN_MASK            (0x20)
-#define SNVS_LPCR_DP_EN(x)              (((uint32_t)(((uint32_t)(x)) << 5)) & 0x20)
-#define SNVS_LPCR_TOP_MASK              (0x40)
-#define SNVS_LPCR_TOP(x)                (((uint32_t)(((uint32_t)(x)) << 6)) & 0x40)
-#define SNVS_LPCR_PWR_GLITCH_EN_MASK    (0x80)
-#define SNVS_LPCR_PWR_GLITCH_EN(x)      (((uint32_t)(((uint32_t)(x)) << 7)) & 0x80)
-#define SNVS_LPCR_LPCALB_EN_MASK        (0x100)
-#define SNVS_LPCR_LPCALB_EN(x)          (((uint32_t)(((uint32_t)(x)) << 8)) & 0x100)
-#define SNVS_LPCR_LPCALB_VAL_MASK       (0x7C00)
-#define SNVS_LPCR_LPCALB_VAL(x)         (((uint32_t)(((uint32_t)(x)) << 10)) & 0x7C00)
-#define SNVS_LPCR_BTN_PRESS_TIME_MASK   (0x30000)
-#define SNVS_LPCR_BTN_PRESS_TIME(x)     (((uint32_t)(((uint32_t)(x)) << 16)) & 0x30000)
-#define SNVS_LPCR_DEBOUNCE_MASK         (0xC0000)
-#define SNVS_LPCR_DEBOUNCE(x)           (((uint32_t)(((uint32_t)(x)) << 18)) & 0xC0000)
-#define SNVS_LPCR_ON_TIME_MASK          (0x300000)
-#define SNVS_LPCR_ON_TIME(x)            (((uint32_t)(((uint32_t)(x)) << 20)) & 0x300000)
-#define SNVS_LPCR_PK_EN_MASK            (0x400000)
-#define SNVS_LPCR_PK_EN(x)              (((uint32_t)(((uint32_t)(x)) << 22)) & 0x400000)
-#define SNVS_LPCR_PK_OVERRIDE_MASK      (0x800000)
-#define SNVS_LPCR_PK_OVERRIDE(x)        (((uint32_t)(((uint32_t)(x)) << 23)) & 0x800000)
-#define SNVS_LPCR_GPR_Z_DIS_MASK        (0x1000000)
-#define SNVS_LPCR_GPR_Z_DIS(x)          (((uint32_t)(((uint32_t)(x)) << 24)) & 0x1000000)
-#define SNVS_LPSR_LPTA                  (0x1)
+#define SNVS_LPCR_SRTC_ENV		((uint32_t)(1 << 0))
+#define SNVS_LPCR_MC_ENV		((uint32_t)(1 << 2))
+#define SNVS_LPCR_LPWUI_EN		((uint32_t)(1 << 3))
+#define SNVS_LPCR_DP_EN			((uint32_t)(1 << 5))
+#define SNVS_LPCR_TOP			((uint32_t)(1 << 6))
+#define SNVS_LPCR_PWR_GLITCH_EN		((uint32_t)(1 << 7))
+#define SNVS_LPCR_BTN_PRESS_TIME(n)	((uint32_t)(((n) & 0x03) << 16))
+#define SNVS_LPCR_DEBOUNCE(n)		((uint32_t)(((n) & 0x03) << 18))
+#define SNVS_LPCR_ON_TIME(n)		((uint32_t)(((n) & 0x03) << 20))
+#define SNVS_LPCR_PK_EN			((uint32_t)(1 << 22))
+#define SNVS_LPCR_PK_OVERRIDE		((uint32_t)(1 << 23))
 
 // 51.5: page 2938
 #define IMXRT_SPDIF		(*(IMXRT_REGISTER32_t *)0x40380000)

teensy4/rtc.c

+/* Teensyduino Core Library
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2019 PJRC.COM, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * 1. The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * 2. If the Software is incorporated into a build system that allows 
+ * selection among a list of target devices, then similar target
+ * devices manufactured by PJRC.COM must be included in the list of
+ * target devices and selectable in the same manner.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "imxrt.h"
+#include "debug/printf.h"
+
+
+unsigned long rtc_get(void)
+{
+	uint32_t hi1 = SNVS_HPRTCMR;
+	uint32_t lo1 = SNVS_HPRTCLR;
+	while (1) {
+		uint32_t hi2 = SNVS_HPRTCMR;
+		uint32_t lo2 = SNVS_HPRTCLR;
+		if (lo1 == lo2 && hi1 == hi2) {
+			return (hi2 << 17) | (lo2 >> 15);
+		}
+		hi1 = hi2;
+		lo1 = lo2;
+	}
+}
+
+void rtc_set(unsigned long t)
+{
+	SNVS_HPCR &= ~SNVS_HPCR_RTC_EN;
+	while (SNVS_HPCR & SNVS_HPCR_RTC_EN) ; // wait
+	SNVS_HPRTCLR = t << 15;
+	SNVS_HPRTCMR = t >> 17;
+	SNVS_HPCR |= SNVS_HPCR_RTC_EN;
+}
+
+void rtc_compensate(int adjust)
+{
+}
+

teensy4/startup.c

 	set_arm_clock(600000000);
 	//set_arm_clock(984000000); Ludicrous Speed
 
+	// initialize RTC
+	if (!(SNVS_LPCR & SNVS_LPCR_SRTC_ENV)) {
+		// if SRTC isn't running, start it with default Jan 1, 2019
+		SNVS_LPSRTCLR = 1546300800u << 15;
+		SNVS_LPSRTCMR = 1546300800u >> 17;
+		SNVS_LPCR |= SNVS_LPCR_SRTC_ENV;
+	}
+	SNVS_HPCR |= SNVS_HPCR_RTC_EN | SNVS_HPCR_HP_TS;
+
 	while (millis() < 20) ; // wait at least 20ms before starting USB
 	usb_init();
 	analog_init();