Split HAL Digital Implementation files (#59)

Split to match the new headers. Uses a namespace 'hal' for internal functions and globals.
SPIAccumulator merged back into SPI header, as it was not a good split. Analog
accumulator will move back to analog input when the analog split is done.

hal/lib/athena/DigitalInternal.cpp

@@ -0,0 +1,129 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "DigitalInternal.h"
+
+#include <math.h>
+#include <stdio.h>
+
+#include <mutex>
+
+#include "ChipObject.h"
+#include "FRC_NetworkCommunication/LoadOut.h"
+#include "HAL/HAL.h"
+#include "HAL/Port.h"
+#include "HAL/cpp/Resource.h"
+#include "HAL/cpp/priority_mutex.h"
+
+static_assert(sizeof(uint32_t) <= sizeof(void*),
+              "This file shoves uint32_ts into pointers.");
+namespace hal {
+// Create a mutex to protect changes to the DO PWM config
+priority_recursive_mutex digitalPwmMutex;
+
+tDIO* digitalSystem = nullptr;
+tRelay* relaySystem = nullptr;
+tPWM* pwmSystem = nullptr;
+hal::Resource* DIOChannels = nullptr;
+hal::Resource* DO_PWMGenerators = nullptr;
+hal::Resource* PWMChannels = nullptr;
+
+bool digitalSystemsInitialized = false;
+
+/**
+ * Initialize the digital system.
+ */
+void initializeDigital(int32_t* status) {
+  if (digitalSystemsInitialized) return;
+
+  hal::Resource::CreateResourceObject(&DIOChannels,
+                                      tDIO::kNumSystems * kDigitalPins);
+  hal::Resource::CreateResourceObject(
+      &DO_PWMGenerators,
+      tDIO::kNumPWMDutyCycleAElements + tDIO::kNumPWMDutyCycleBElements);
+  hal::Resource::CreateResourceObject(&PWMChannels,
+                                      tPWM::kNumSystems * kPwmPins);
+  digitalSystem = tDIO::create(status);
+
+  // Relay Setup
+  relaySystem = tRelay::create(status);
+
+  // Turn off all relay outputs.
+  relaySystem->writeValue_Forward(0, status);
+  relaySystem->writeValue_Reverse(0, status);
+
+  // PWM Setup
+  pwmSystem = tPWM::create(status);
+
+  // Make sure that the 9403 IONode has had a chance to initialize before
+  // continuing.
+  while (pwmSystem->readLoopTiming(status) == 0) delayTicks(1);
+
+  if (pwmSystem->readLoopTiming(status) != kExpectedLoopTiming) {
+    // TODO: char err[128];
+    // TODO: sprintf(err, "DIO LoopTiming: %d, expecting: %lu\n",
+    // digitalModules[port->module-1]->readLoopTiming(status),
+    // kExpectedLoopTiming);
+    *status = LOOP_TIMING_ERROR;  // NOTE: Doesn't display the error
+  }
+
+  // Calculate the length, in ms, of one DIO loop
+  double loopTime = pwmSystem->readLoopTiming(status) /
+                    (kSystemClockTicksPerMicrosecond * 1e3);
+
+  pwmSystem->writeConfig_Period((uint16_t)(kDefaultPwmPeriod / loopTime + .5),
+                                status);
+  uint16_t minHigh = (uint16_t)(
+      (kDefaultPwmCenter - kDefaultPwmStepsDown * loopTime) / loopTime + .5);
+  pwmSystem->writeConfig_MinHigh(minHigh, status);
+  //  printf("MinHigh: %d\n", minHigh);
+  // Ensure that PWM output values are set to OFF
+  for (uint32_t pwm_index = 0; pwm_index < kPwmPins; pwm_index++) {
+    // Initialize port structure
+    DigitalPort digital_port;
+    digital_port.port.pin = pwm_index;
+
+    setPWM(&digital_port, kPwmDisabled, status);
+    setPWMPeriodScale(&digital_port, 3, status);  // Set all to 4x by default.
+  }
+
+  digitalSystemsInitialized = true;
+}
+
+/**
+ * Map DIO pin numbers from their physical number (10 to 26) to their position
+ * in the bit field.
+ */
+uint32_t remapMXPChannel(uint32_t pin) { return pin - 10; }
+
+uint32_t remapMXPPWMChannel(uint32_t pin) {
+  if (pin < 14) {
+    return pin - 10;  // first block of 4 pwms (MXP 0-3)
+  } else {
+    return pin - 6;  // block of PWMs after SPI
+  }
+}
+
+/**
+ * remap the digital source pin and set the module.
+ * If it's an analog trigger, determine the module from the high order routing
+ * channel else do normal digital input remapping based on pin number (MXP)
+ */
+extern "C++" void remapDigitalSource(bool analogTrigger, uint32_t& pin,
+                                     uint8_t& module) {
+  if (analogTrigger) {
+    module = pin >> 4;
+  } else {
+    if (pin >= kNumHeaders) {
+      pin = remapMXPChannel(pin);
+      module = 1;
+    } else {
+      module = 0;
+    }
+  }
+}
+}