diff --git a/hal/include/HAL/Counter.h b/hal/include/HAL/Counter.h
index 7566d4874b..720886f863 100644
--- a/hal/include/HAL/Counter.h
+++ b/hal/include/HAL/Counter.h
@@ -54,7 +54,7 @@ void HAL_SetCounterPulseLengthMode(HAL_CounterHandle counterHandle,
 int32_t HAL_GetCounterSamplesToAverage(HAL_CounterHandle counterHandle,
                                        int32_t* status);
 void HAL_SetCounterSamplesToAverage(HAL_CounterHandle counterHandle,
-                                    int samplesToAverage, int32_t* status);
+                                    int32_t samplesToAverage, int32_t* status);
 void HAL_ResetCounter(HAL_CounterHandle counterHandle, int32_t* status);
 int32_t HAL_GetCounter(HAL_CounterHandle counterHandle, int32_t* status);
 double HAL_GetCounterPeriod(HAL_CounterHandle counterHandle, int32_t* status);
diff --git a/hal/include/HAL/DriverStation.h b/hal/include/HAL/DriverStation.h
index 4a4d6073e0..8505ddbaf7 100644
--- a/hal/include/HAL/DriverStation.h
+++ b/hal/include/HAL/DriverStation.h
@@ -54,12 +54,12 @@ enum HAL_AllianceStationID {
 #define HAL_kMaxJoystickPOVs 12
 
 struct HAL_JoystickAxes {
-  uint16_t count;
+  int16_t count;
   float axes[HAL_kMaxJoystickAxes];
 };
 
 struct HAL_JoystickPOVs {
-  uint16_t count;
+  int16_t count;
   int16_t povs[HAL_kMaxJoystickPOVs];
 };
 
diff --git a/hal/include/HAL/Task.h b/hal/include/HAL/Task.h
index d54bc876da..dce8dcba47 100644
--- a/hal/include/HAL/Task.h
+++ b/hal/include/HAL/Task.h
@@ -12,7 +12,7 @@
 
 #ifndef _STATUS_DEFINED
 #define _STATUS_DEFINED
-typedef int STATUS;
+typedef int32_t STATUS;
 #endif /* _STATUS_DEFINED */
 
 #ifndef OK
@@ -33,8 +33,11 @@ extern "C" {
 const int32_t HAL_TaskLib_ILLEGAL_PRIORITY = 22;  // 22 is EINVAL
 
 STATUS HAL_VerifyTaskID(TASK task);
-STATUS HAL_SetTaskPriority(TASK task, int priority);  // valid priority [1..99]
-STATUS HAL_GetTaskPriority(TASK task, int* priority);
+
+// valid priority [1..99]
+STATUS HAL_SetTaskPriority(TASK task, int32_t priority);
+
+STATUS HAL_GetTaskPriority(TASK task, int32_t* priority);
 #ifdef __cplusplus
 }
 #endif
diff --git a/hal/include/HAL/cpp/Semaphore.h b/hal/include/HAL/cpp/Semaphore.h
index 82af7cc5d6..140749467e 100644
--- a/hal/include/HAL/cpp/Semaphore.h
+++ b/hal/include/HAL/cpp/Semaphore.h
@@ -15,7 +15,7 @@
 
 class Semaphore {
  public:
-  explicit Semaphore(uint32_t count = 0);
+  explicit Semaphore(int32_t count = 0);
   Semaphore(Semaphore&&);
   Semaphore& operator=(Semaphore&&);
 
@@ -28,11 +28,11 @@ class Semaphore {
   static const int32_t kNoWait = 0;
   static const int32_t kWaitForever = -1;
 
-  static const uint32_t kEmpty = 0;
-  static const uint32_t kFull = 1;
+  static const int32_t kEmpty = 0;
+  static const int32_t kFull = 1;
 
  private:
   priority_mutex m_mutex;
   std::condition_variable_any m_condition;
-  uint32_t m_count = 0;
+  int32_t m_count = 0;
 };
diff --git a/hal/lib/athena/Accelerometer.cpp b/hal/lib/athena/Accelerometer.cpp
index a9f012a136..6cc71ac2cd 100644
--- a/hal/lib/athena/Accelerometer.cpp
+++ b/hal/lib/athena/Accelerometer.cpp
@@ -216,7 +216,7 @@ void HAL_SetAccelerometerRange(HAL_AccelerometerRange range) {
 double HAL_GetAccelerometerX() {
   initializeAccelerometer();
 
-  int raw =
+  int32_t raw =
       (readRegister(kReg_OutXMSB) << 4) | (readRegister(kReg_OutXLSB) >> 4);
   return unpackAxis(raw);
 }
@@ -229,7 +229,7 @@ double HAL_GetAccelerometerX() {
 double HAL_GetAccelerometerY() {
   initializeAccelerometer();
 
-  int raw =
+  int32_t raw =
       (readRegister(kReg_OutYMSB) << 4) | (readRegister(kReg_OutYLSB) >> 4);
   return unpackAxis(raw);
 }
@@ -242,7 +242,7 @@ double HAL_GetAccelerometerY() {
 double HAL_GetAccelerometerZ() {
   initializeAccelerometer();
 
-  int raw =
+  int32_t raw =
       (readRegister(kReg_OutZMSB) << 4) | (readRegister(kReg_OutZLSB) >> 4);
   return unpackAxis(raw);
 }
diff --git a/hal/lib/athena/AnalogAccumulator.cpp b/hal/lib/athena/AnalogAccumulator.cpp
index 58f55ca7e4..3a5cf9fa58 100644
--- a/hal/lib/athena/AnalogAccumulator.cpp
+++ b/hal/lib/athena/AnalogAccumulator.cpp
@@ -26,7 +26,7 @@ HAL_Bool HAL_IsAccumulatorChannel(HAL_AnalogInputHandle analogPortHandle,
     *status = HAL_HANDLE_ERROR;
     return false;
   }
-  for (uint32_t i = 0; i < kNumAccumulators; i++) {
+  for (int32_t i = 0; i < kNumAccumulators; i++) {
     if (port->channel == kAccumulatorChannels[i]) return true;
   }
   return false;
diff --git a/hal/lib/athena/AnalogInput.cpp b/hal/lib/athena/AnalogInput.cpp
index 3ce156b389..8717e2afbc 100644
--- a/hal/lib/athena/AnalogInput.cpp
+++ b/hal/lib/athena/AnalogInput.cpp
@@ -375,7 +375,7 @@ int32_t HAL_GetAnalogLSBWeight(HAL_AnalogInputHandle analogPortHandle,
     *status = HAL_HANDLE_ERROR;
     return 0;
   }
-  uint32_t lsbWeight = FRC_NetworkCommunication_nAICalibration_getLSBWeight(
+  int32_t lsbWeight = FRC_NetworkCommunication_nAICalibration_getLSBWeight(
       0, port->channel, status);  // XXX: aiSystemIndex == 0?
   return lsbWeight;
 }
diff --git a/hal/lib/athena/AnalogInternal.cpp b/hal/lib/athena/AnalogInternal.cpp
index b4730a9f76..f734f26549 100644
--- a/hal/lib/athena/AnalogInternal.cpp
+++ b/hal/lib/athena/AnalogInternal.cpp
@@ -21,7 +21,7 @@ IndexedHandleResource<HAL_AnalogInputHandle, hal::AnalogPort, kNumAnalogInputs,
                       HAL_HandleEnum::AnalogInput>
     analogInputHandles;
 
-static uint32_t analogNumChannelsToActivate = 0;
+static int32_t analogNumChannelsToActivate = 0;
 
 bool analogSystemInitialized = false;
 
@@ -43,8 +43,8 @@ void initializeAnalog(int32_t* status) {
  *
  * @return Active channels.
  */
-uint32_t getAnalogNumActiveChannels(int32_t* status) {
-  uint32_t scanSize = analogInputSystem->readConfig_ScanSize(status);
+int32_t getAnalogNumActiveChannels(int32_t* status) {
+  int32_t scanSize = analogInputSystem->readConfig_ScanSize(status);
   if (scanSize == 0) return 8;
   return scanSize;
 }
@@ -60,7 +60,7 @@ uint32_t getAnalogNumActiveChannels(int32_t* status) {
  *
  * @return Value to write to the active channels field.
  */
-uint32_t getAnalogNumChannelsToActivate(int32_t* status) {
+int32_t getAnalogNumChannelsToActivate(int32_t* status) {
   if (analogNumChannelsToActivate == 0)
     return getAnalogNumActiveChannels(status);
   return analogNumChannelsToActivate;
@@ -75,7 +75,7 @@ uint32_t getAnalogNumChannelsToActivate(int32_t* status) {
  *
  * @param channels Number of active channels.
  */
-void setAnalogNumChannelsToActivate(uint32_t channels) {
+void setAnalogNumChannelsToActivate(int32_t channels) {
   analogNumChannelsToActivate = channels;
 }
 }  // namespace hal
diff --git a/hal/lib/athena/AnalogInternal.h b/hal/lib/athena/AnalogInternal.h
index 1ffe3f82df..faad09c3d0 100644
--- a/hal/lib/athena/AnalogInternal.h
+++ b/hal/lib/athena/AnalogInternal.h
@@ -37,9 +37,9 @@ extern IndexedHandleResource<HAL_AnalogInputHandle, hal::AnalogPort,
                              kNumAnalogInputs, HAL_HandleEnum::AnalogInput>
     analogInputHandles;
 
-uint32_t getAnalogNumActiveChannels(int32_t* status);
-uint32_t getAnalogNumChannelsToActivate(int32_t* status);
-void setAnalogNumChannelsToActivate(uint32_t channels);
+int32_t getAnalogNumActiveChannels(int32_t* status);
+int32_t getAnalogNumChannelsToActivate(int32_t* status);
+void setAnalogNumChannelsToActivate(int32_t channels);
 void initializeAnalog(int32_t* status);
 
 extern bool analogSystemInitialized;
diff --git a/hal/lib/athena/DIO.cpp b/hal/lib/athena/DIO.cpp
index 6d665a1bb3..3132fa85f0 100644
--- a/hal/lib/athena/DIO.cpp
+++ b/hal/lib/athena/DIO.cpp
@@ -383,7 +383,7 @@ HAL_Bool HAL_IsAnyPulsing(int32_t* status) {
  * @param filterIndex The filter index.  Must be in the range 0 - 3, where 0
  *                    means "none" and 1 - 3 means filter # filterIndex - 1.
  */
-void HAL_SetFilterSelect(HAL_DigitalHandle dioPortHandle, int filterIndex,
+void HAL_SetFilterSelect(HAL_DigitalHandle dioPortHandle, int32_t filterIndex,
                          int32_t* status) {
   auto port = digitalChannelHandles.Get(dioPortHandle, HAL_HandleEnum::DIO);
   if (port == nullptr) {
@@ -408,7 +408,7 @@ void HAL_SetFilterSelect(HAL_DigitalHandle dioPortHandle, int filterIndex,
  * @return filterIndex The filter index.  Must be in the range 0 - 3,
  * where 0 means "none" and 1 - 3 means filter # filterIndex - 1.
  */
-int HAL_GetFilterSelect(HAL_DigitalHandle dioPortHandle, int32_t* status) {
+int32_t HAL_GetFilterSelect(HAL_DigitalHandle dioPortHandle, int32_t* status) {
   auto port = digitalChannelHandles.Get(dioPortHandle, HAL_HandleEnum::DIO);
   if (port == nullptr) {
     *status = HAL_HANDLE_ERROR;
diff --git a/hal/lib/athena/DigitalInternal.h b/hal/lib/athena/DigitalInternal.h
index 00d4ba7013..2adecdf833 100644
--- a/hal/lib/athena/DigitalInternal.h
+++ b/hal/lib/athena/DigitalInternal.h
@@ -23,9 +23,9 @@ namespace hal {
 /**
  * MXP channels when used as digital output PWM are offset from actual value
  */
-constexpr uint32_t kMXPDigitalPWMOffset = 6;
+constexpr int32_t kMXPDigitalPWMOffset = 6;
 
-constexpr uint32_t kExpectedLoopTiming = 40;
+constexpr int32_t kExpectedLoopTiming = 40;
 
 /**
  * kDefaultPwmPeriod is in ms
diff --git a/hal/lib/athena/Encoder.cpp b/hal/lib/athena/Encoder.cpp
index 62c25c9655..b611048032 100644
--- a/hal/lib/athena/Encoder.cpp
+++ b/hal/lib/athena/Encoder.cpp
@@ -172,7 +172,7 @@ void Encoder::SetReverseDirection(bool reverseDirection, int32_t* status) {
   }
 }
 
-void Encoder::SetSamplesToAverage(int samplesToAverage, int32_t* status) {
+void Encoder::SetSamplesToAverage(int32_t samplesToAverage, int32_t* status) {
   if (samplesToAverage < 1 || samplesToAverage > 127) {
     *status = PARAMETER_OUT_OF_RANGE;
     return;
diff --git a/hal/lib/athena/EncoderInternal.h b/hal/lib/athena/EncoderInternal.h
index 87488981d6..ede7577b81 100644
--- a/hal/lib/athena/EncoderInternal.h
+++ b/hal/lib/athena/EncoderInternal.h
@@ -36,7 +36,7 @@ class Encoder {
   void SetMinRate(double minRate, int32_t* status);
   void SetDistancePerPulse(double distancePerPulse, int32_t* status);
   void SetReverseDirection(bool reverseDirection, int32_t* status);
-  void SetSamplesToAverage(int samplesToAverage, int32_t* status);
+  void SetSamplesToAverage(int32_t samplesToAverage, int32_t* status);
   int32_t GetSamplesToAverage(int32_t* status) const;
 
   void SetIndexSource(HAL_Handle digitalSourceHandle,
diff --git a/hal/lib/athena/FRCDriverStation.cpp b/hal/lib/athena/FRCDriverStation.cpp
index 6f63e4e4c8..2c86fd7807 100644
--- a/hal/lib/athena/FRCDriverStation.cpp
+++ b/hal/lib/athena/FRCDriverStation.cpp
@@ -14,8 +14,11 @@
 #include "HAL/cpp/priority_condition_variable.h"
 #include "HAL/cpp/priority_mutex.h"
 
+static_assert(sizeof(int32_t) >= sizeof(int),
+              "FRC_NetworkComm status variable is larger than 32 bits");
+
 struct HAL_JoystickAxesInt {
-  uint16_t count;
+  int16_t count;
   int16_t axes[HAL_kMaxJoystickAxes];
 };
 
@@ -95,11 +98,11 @@ int32_t HAL_GetJoystickAxes(int32_t joystickNum, HAL_JoystickAxes* axes) {
       joystickNum, reinterpret_cast<JoystickAxes_t*>(&axesInt),
       HAL_kMaxJoystickAxes);
 
-  // copy int values to float values
+  // copy integer values to float values
   axes->count = axesInt.count;
   // current scaling is -128 to 127, can easily be patched in the future by
   // changing this function.
-  for (unsigned int i = 0; i < axesInt.count; i++) {
+  for (int32_t i = 0; i < axesInt.count; i++) {
     int8_t value = axesInt.axes[i];
     if (value < 0) {
       axes->axes[i] = value / 128.0f;
diff --git a/hal/lib/athena/Notifier.cpp b/hal/lib/athena/Notifier.cpp
index cf300e08a1..8a74b87495 100644
--- a/hal/lib/athena/Notifier.cpp
+++ b/hal/lib/athena/Notifier.cpp
@@ -20,7 +20,7 @@
 #include "HAL/cpp/priority_mutex.h"
 #include "HAL/handles/UnlimitedHandleResource.h"
 
-static const uint32_t kTimerInterruptNumber = 28;
+static const int32_t kTimerInterruptNumber = 28;
 
 static priority_mutex notifierInterruptMutex;
 static priority_recursive_mutex notifierMutex;
diff --git a/hal/lib/athena/SPI.cpp b/hal/lib/athena/SPI.cpp
index d4fc5ccbf8..6dd4d43927 100644
--- a/hal/lib/athena/SPI.cpp
+++ b/hal/lib/athena/SPI.cpp
@@ -342,12 +342,12 @@ static void spiAccumulatorProcess(uint64_t currentTime,
   // convert from bytes
   uint32_t resp = 0;
   if (accum->bigEndian) {
-    for (int i = 0; i < accum->xferSize; ++i) {
+    for (int32_t i = 0; i < accum->xferSize; ++i) {
       resp <<= 8;
       resp |= resp_b[i] & 0xff;
     }
   } else {
-    for (int i = accum->xferSize - 1; i >= 0; --i) {
+    for (int32_t i = accum->xferSize - 1; i >= 0; --i) {
       resp <<= 8;
       resp |= resp_b[i] & 0xff;
     }
@@ -408,7 +408,7 @@ void HAL_InitSPIAccumulator(int32_t port, int32_t period, int32_t cmd,
     spiAccumulators[port] = std::make_unique<SPIAccumulator>();
   SPIAccumulator* accum = spiAccumulators[port].get();
   if (bigEndian) {
-    for (int i = xferSize - 1; i >= 0; --i) {
+    for (int32_t i = xferSize - 1; i >= 0; --i) {
       accum->cmd[i] = cmd & 0xff;
       cmd >>= 8;
     }
diff --git a/hal/lib/athena/SerialPort.cpp b/hal/lib/athena/SerialPort.cpp
index 07ed3f18a2..21c1b19d0f 100644
--- a/hal/lib/athena/SerialPort.cpp
+++ b/hal/lib/athena/SerialPort.cpp
@@ -9,8 +9,8 @@
 
 #include "visa/visa.h"
 
-static uint32_t m_resourceManagerHandle;
-static uint32_t m_portHandle[2];
+static int32_t m_resourceManagerHandle;
+static int32_t m_portHandle[2];
 
 extern "C" {
 
diff --git a/hal/lib/athena/Solenoid.cpp b/hal/lib/athena/Solenoid.cpp
index e0be4f06f7..756f3f7906 100644
--- a/hal/lib/athena/Solenoid.cpp
+++ b/hal/lib/athena/Solenoid.cpp
@@ -118,7 +118,7 @@ void HAL_SetSolenoid(HAL_SolenoidHandle solenoidPortHandle, HAL_Bool value,
 
 int32_t HAL_GetPCMSolenoidBlackList(int32_t module, int32_t* status) {
   if (!checkPCMInit(module, status)) return 0;
-  UINT8 value;
+  uint8_t value;
 
   *status = PCM_modules[module]->GetSolenoidBlackList(value);
 
diff --git a/hal/lib/athena/Task.cpp b/hal/lib/athena/Task.cpp
index 9cd17aa758..c91d6cada2 100644
--- a/hal/lib/athena/Task.cpp
+++ b/hal/lib/athena/Task.cpp
@@ -26,8 +26,8 @@ STATUS HAL_VerifyTaskID(TASK task) {
   }
 }
 
-STATUS HAL_SetTaskPriority(TASK task, int priority) {
-  int policy = 0;
+STATUS HAL_SetTaskPriority(TASK task, int32_t priority) {
+  int32_t policy = 0;
   struct sched_param param;
 
   if (HAL_VerifyTaskID(task) == OK &&
@@ -43,8 +43,8 @@ STATUS HAL_SetTaskPriority(TASK task, int priority) {
   }
 }
 
-STATUS HAL_GetTaskPriority(TASK task, int* priority) {
-  int policy = 0;
+STATUS HAL_GetTaskPriority(TASK task, int32_t* priority) {
+  int32_t policy = 0;
   struct sched_param param;
 
   if (HAL_VerifyTaskID(task) == OK &&
diff --git a/hal/lib/athena/cpp/Semaphore.cpp b/hal/lib/athena/cpp/Semaphore.cpp
index 64f3ed1c97..0b017b8647 100644
--- a/hal/lib/athena/cpp/Semaphore.cpp
+++ b/hal/lib/athena/cpp/Semaphore.cpp
@@ -7,7 +7,7 @@
 
 #include "HAL/cpp/Semaphore.h"
 
-Semaphore::Semaphore(uint32_t count) { m_count = count; }
+Semaphore::Semaphore(int32_t count) { m_count = count; }
 
 void Semaphore::give() {
   std::lock_guard<priority_mutex> lock(m_mutex);