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Diffstat (limited to 'src/machine/machine_atsamd51.go')
-rw-r--r--src/machine/machine_atsamd51.go49
1 files changed, 49 insertions, 0 deletions
diff --git a/src/machine/machine_atsamd51.go b/src/machine/machine_atsamd51.go
index 7c4c4d07c..8d37f2fa5 100644
--- a/src/machine/machine_atsamd51.go
+++ b/src/machine/machine_atsamd51.go
@@ -2299,3 +2299,52 @@ func checkFlashError() error {
return nil
}
+
+// Watchdog provides access to the hardware watchdog available
+// in the SAMD51.
+var Watchdog = &watchdogImpl{}
+
+const (
+ // WatchdogMaxTimeout in milliseconds (16s)
+ WatchdogMaxTimeout = (16384 * 1000) / 1024 // CYC16384/1024kHz
+)
+
+type watchdogImpl struct{}
+
+// Configure the watchdog.
+//
+// This method should not be called after the watchdog is started and on
+// some platforms attempting to reconfigure after starting the watchdog
+// is explicitly forbidden / will not work.
+func (wd *watchdogImpl) Configure(config WatchdogConfig) error {
+ // 1.024kHz clock
+ cycles := int((int64(config.TimeoutMillis) * 1024) / 1000)
+
+ // period is expressed as a power-of-two, starting at 8 / 1024ths of a second
+ period := uint8(0)
+ cfgCycles := 8
+ for cfgCycles < cycles {
+ period++
+ cfgCycles <<= 1
+
+ if period >= 0xB {
+ break
+ }
+ }
+
+ sam.WDT.CONFIG.Set(period << sam.WDT_CONFIG_PER_Pos)
+
+ return nil
+}
+
+// Starts the watchdog.
+func (wd *watchdogImpl) Start() error {
+ sam.WDT.CTRLA.SetBits(sam.WDT_CTRLA_ENABLE)
+ return nil
+}
+
+// Update the watchdog, indicating that `source` is healthy.
+func (wd *watchdogImpl) Update() {
+ // 0xA5 = magic value (see datasheet)
+ sam.WDT.CLEAR.Set(0xA5)
+}