+#define SAMD21_EVSYS_CONTROL_SWRST 0
+#define SAMD21_EVSYS_CONTROL_GCLKREQ 4
+
+#define SAMD21_EVSYS_CHANNEL_CHANNEL 0
+
+#define SAMD21_EVSYS_CHANNEL_SWEVT 8
+
+#define SAMD21_EVSYS_CHANNEL_EVGEN 16
+#define SAMD21_EVSYS_CHANNEL_EVGEN_NONE 0x00
+#define SAMD21_EVSYS_CHANNEL_EVGEN_RTC_CMP(i) (0x01 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_OVF 0x03
+#define SAMD21_EVSYS_CHANNEL_EVGEN_PER(i) (0x04 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_EXTINT(i) (0x0c + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_DMAC_CH(i) (0x1e + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC0_OVF 0x22
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC0_TRG 0x23
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC0_CNT 0x29
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC0_MCX(i) (0x25 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC1_OVF 0x29
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC1_TRG 0x2a
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC1_CNT 0x2b
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC1_MCX(i) (0x2c + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC2_OVF 0x2e
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC2_TRG 0x2f
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC2_CNT 0x30
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC2_MCX(i) (0x31 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC3_OVF 0x33
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC3_MC(i) (0x34 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC4_OVF 0x36
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC4_MC(i) (0x37 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC5_OVF 0x39
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC5_MC(i) (0x3a + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC6_OVF 0x3c
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC6_MC(i) (0x3d + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC7_OVF 0x3f
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TC7_MC(i) (0x40 + (i))
+#define SAMD21_EVSYS_CHANNEL_EVGEN_ADC_RESRDY 0x42
+#define SAMD21_EVSYS_CHANNEL_EVGEN_ADC_WINMON 0x43
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_COMP0 0x44
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_COMP1 0x45
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_WIN0 0x46
+#define SAMD21_EVSYS_CHANNEL_EVGEN_DAC_EMPTY 0x47
+#define SAMD21_EVSYS_CHANNEL_EVGEN_PTC_EOC 0x48
+#define SAMD21_EVSYS_CHANNEL_EVGEN_PTC_WCOMP 0x49
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_COMP2 0x4a
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_COMP3 0x4b
+#define SAMD21_EVSYS_CHANNEL_EVGEN_AC_WIN1 0x4c
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC3_OVF 0x4d
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC3_TRG 0x4e
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC3_CNT 0x4f
+#define SAMD21_EVSYS_CHANNEL_EVGEN_TCC3_MCX(i) (0x50 + (i))
+
+#define SAMD21_EVSYS_CHANNEL_PATH 24
+#define SAMD21_EVSYS_CHANNEL_PATH_SYNCHRONOUS 0
+#define SAMD21_EVSYS_CHANNEL_PATH_RESYNCHRONIZED 1
+#define SAMD21_EVSYS_CHANNEL_PATH_ASYNCHRONOUS 2
+
+#define SAMD21_EVSYS_CHANNEL_EDGESEL 26
+#define SAMD21_EVSYS_CHANNEL_EDGESEL_NO_EVT_OUTPUT 0
+#define SAMD21_EVSYS_CHANNEL_EDGESEL_RISING_EDGE 1
+#define SAMD21_EVSYS_CHANNEL_EDGESEL_FALLING_EDGE 2
+#define SAMD21_EVSYS_CHANNEL_EDGESEL_BOTH_EDGES 3
+
+#define SAMD21_EVSYS_USER_USER 0
+#define SAMD21_EVSYS_USER_USER_DMAC_CH(n) (0x00 + (n))
+#define SAMD21_EVSYS_USER_USER_TCC0_EV(n) (0x04 + (n))
+#define SAMD21_EVSYS_USER_USER_TCC0_MC(n) (0x06 + (n))
+#define SAMD21_EVSYS_USER_USER_TCC1_EV(n) (0x0a + (n))
+#define SAMD21_EVSYS_USER_USER_TCC1_MC(n) (0x0c + (n))
+#define SAMD21_EVSYS_USER_USER_TCC2_EV(n) (0x0e + (n))
+#define SAMD21_EVSYS_USER_USER_TCC2_MC(n) (0x10 + (n))
+#define SAMD21_EVSYS_USER_USER_TC(n) (0x12 + (n))
+#define SAMD21_EVSYS_USER_USER_ADC_START (0x17)
+#define SAMD21_EVSYS_USER_USER_ADC_SYNC 0x18
+#define SAMD21_EVSYS_USER_USER_AC_COMP0 0x19
+#define SAMD21_EVSYS_USER_USER_AC_COMP1 0x1a
+#define SAMD21_EVSYS_USER_USER_DAC_START 0x1b
+#define SAMD21_EVSYS_USER_USER_PTC_STCONV 0x1c
+#define SAMD21_EVSYS_USER_USER_AC_COMP2 0x1d
+#define SAMD21_EVSYS_USER_USER_AC_COMP3 0x1e
+#define SAMD21_EVSYS_USER_USER_TCC3_EV(n) (0x1f + (n))
+#define SAMD21_EVSYS_USER_USER_TCC3_MC(n) (0x21 + (n))
+
+#define SAMD21_EVSYS_USER_CHANNEL 8
+#define SAMD21_EVSYS_USER_CHANNEL_NONE 0
+#define SAMD21_EVSYS_USER_CHANNEL_NUM(n) ((n) + 1)
+
+
+#define SAMD21_EVSYS_CHSTATUS_USRRDY(n) (((n) & 7) | (((n) & 8) << 1))
+#define SAMD21_EVSYS_CHSTATUS_CHBUSY(n) (((n) & 7) | (((n) & 8) << 1) | 8)
+