diff --git a/hal/lib/athena/DigitalInternal.h b/hal/lib/athena/DigitalInternal.h
new file mode 100644
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--- /dev/null
+++ b/hal/lib/athena/DigitalInternal.h
@@ -0,0 +1,89 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016-2017. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "HAL/AnalogTrigger.h"
+#include "HAL/ChipObject.h"
+#include "HAL/Ports.h"
+#include "HAL/Types.h"
+#include "HAL/handles/DigitalHandleResource.h"
+#include "HAL/handles/HandlesInternal.h"
+#include "PortsInternal.h"
+
+namespace hal {
+/**
+ * MXP channels when used as digital output PWM are offset from actual value
+ */
+constexpr int32_t kMXPDigitalPWMOffset = 6;
+
+constexpr int32_t kExpectedLoopTiming = 40;
+
+/**
+ * kDefaultPwmPeriod is in ms
+ *
+ * - 20ms periods (50 Hz) are the "safest" setting in that this works for all
+ *   devices
+ * - 20ms periods seem to be desirable for Vex Motors
+ * - 20ms periods are the specified period for HS-322HD servos, but work
+ *   reliably down to 10.0 ms; starting at about 8.5ms, the servo sometimes hums
+ *   and get hot; by 5.0ms the hum is nearly continuous
+ * - 10ms periods work well for Victor 884
+ * - 5ms periods allows higher update rates for Luminary Micro Jaguar speed
+ *   controllers. Due to the shipping firmware on the Jaguar, we can't run the
+ *   update period less than 5.05 ms.
+ *
+ * kDefaultPwmPeriod is the 1x period (5.05 ms).  In hardware, the period
+ * scaling is implemented as an output squelch to get longer periods for old
+ * devices.
+ */
+constexpr double kDefaultPwmPeriod = 5.05;
+/**
+ * kDefaultPwmCenter is the PWM range center in ms
+ */
+constexpr double kDefaultPwmCenter = 1.5;
+/**
+ * kDefaultPWMStepsDown is the number of PWM steps below the centerpoint
+ */
+constexpr int32_t kDefaultPwmStepsDown = 1000;
+constexpr int32_t kPwmDisabled = 0;
+
+// Create a mutex to protect changes to the DO PWM config
+extern priority_recursive_mutex digitalPwmMutex;
+
+extern std::unique_ptr<tDIO> digitalSystem;
+extern std::unique_ptr<tRelay> relaySystem;
+extern std::unique_ptr<tPWM> pwmSystem;
+extern std::unique_ptr<tSPI> spiSystem;
+
+struct DigitalPort {
+  uint8_t channel;
+  bool configSet = false;
+  bool eliminateDeadband = false;
+  int32_t maxPwm = 0;
+  int32_t deadbandMaxPwm = 0;
+  int32_t centerPwm = 0;
+  int32_t deadbandMinPwm = 0;
+  int32_t minPwm = 0;
+};
+
+extern DigitalHandleResource<HAL_DigitalHandle, DigitalPort,
+                             kNumDigitalChannels + kNumPWMHeaders>
+    digitalChannelHandles;
+
+void initializeDigital(int32_t* status);
+bool remapDigitalSource(HAL_Handle digitalSourceHandle,
+                        HAL_AnalogTriggerType analogTriggerType,
+                        uint8_t& channel, uint8_t& module, bool& analogTrigger);
+int32_t remapSPIChannel(int32_t channel);
+int32_t remapMXPPWMChannel(int32_t channel);
+int32_t remapMXPChannel(int32_t channel);
+}  // namespace hal