diff --git a/Machines/Enterprise/Dave.cpp b/Machines/Enterprise/Dave.cpp
index 7d354f98c..3b7ca2ab0 100644
--- a/Machines/Enterprise/Dave.cpp
+++ b/Machines/Enterprise/Dave.cpp
@@ -200,10 +200,29 @@ uint8_t TimedInterruptSource::get_new_interrupts() {
 }
 
 void TimedInterruptSource::write(uint16_t address, uint8_t value) {
-	(void)address;
-	(void)value;
+	address &= 15;
+	switch(address) {
+		default: break;
+
+		case 0: case 2:
+			channels_[address >> 1].reload = (channels_[address >> 1].reload & 0xff00) | value;
+		break;
+		case 1:	case 3:
+			channels_[address >> 1].reload = uint16_t((channels_[address >> 1].reload & 0x00ff) | ((value & 0xf) << 8));
+		break;
+
+		case 7:
+			channels_[0].sync = value & 0x01;
+			channels_[1].sync = value & 0x02;
+			rate_ = InterruptRate((value >> 5) & 3);
+		break;
+	}
 }
 
 void TimedInterruptSource::run_for(Cycles cycles) {
 	(void)cycles;
 }
+
+Cycles TimedInterruptSource::get_next_sequence_point() const {
+	return Cycles::max();
+}
diff --git a/Machines/Enterprise/Dave.hpp b/Machines/Enterprise/Dave.hpp
index 3953bc211..92b14bafb 100644
--- a/Machines/Enterprise/Dave.hpp
+++ b/Machines/Enterprise/Dave.hpp
@@ -125,8 +125,22 @@ class TimedInterruptSource {
 
 		void run_for(Cycles);
 
+		Cycles get_next_sequence_point() const;
+
 	private:
 		uint8_t interrupts_ = 0;
+
+		enum class InterruptRate {
+			OnekHz,
+			FiftyHz,
+			ToneGenerator0,
+			ToneGenerator1,
+		} rate_ = InterruptRate::OnekHz;
+
+		struct Channel {
+			uint16_t value, reload;
+			bool sync;
+		} channels_[2];
 };
 
 }