RIOT/pkg/arduino_sdi_12/patches/0003-RIOT-Fix-for-SAMD-boards.patch

From ff9eba693d589c8241b02e8c29a176a55c665816 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=2E=20David=20Ib=C3=A1=C3=B1ez?= <jdavid.ibp@gmail.com>
Date: Tue, 11 Jan 2022 13:09:40 +0100
Subject: [PATCH 3/3] RIOT: Fix for SAMD boards
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Using RIOT's API it works, tested with the feather-m0 board, otherwise
it hangs.

Signed-off-by: J. David Ibáñez <jdavid.ibp@gmail.com>
---
 src/SDI12.cpp        |  4 +-
 src/SDI12_boards.cpp | 58 ---------------------------
 src/SDI12_boards.h   | 93 --------------------------------------------
 3 files changed, 1 insertion(+), 154 deletions(-)

diff --git a/src/SDI12.cpp b/src/SDI12.cpp
index 477b16d..f83c6fe 100644
--- a/src/SDI12.cpp
+++ b/src/SDI12.cpp
@@ -241,7 +241,6 @@ SDI12::~SDI12() {
   setState(SDI12_DISABLED);
   if (isActive()) { _activeObject = NULL; }
   // Set the timer prescalers back to original values
-  // NOTE:  This does NOT reset SAMD board pre-scalers!
   sdi12timer.resetSDI12TimerPrescale();
 }
 
@@ -264,7 +263,6 @@ void SDI12::end() {
   setState(SDI12_DISABLED);
   _activeObject = nullptr;
   // Set the timer prescalers back to original values
-  // NOTE:  This does NOT reset SAMD board pre-scalers!
   sdi12timer.resetSDI12TimerPrescale();
 }
 
@@ -319,7 +317,7 @@ uint8_t SDI12::parity_even_bit(uint8_t v) {
 
 // a helper function to switch pin interrupts on or off
 void SDI12::setPinInterrupts(bool enable) {
-#if defined(ARDUINO_ARCH_SAMD) || defined(ESP32) || defined(ESP8266)
+#if defined(ESP32) || defined(ESP8266)
   // Merely need to attach the interrupt function to the pin
   if (enable) attachInterrupt(digitalPinToInterrupt(_dataPin), handleInterrupt, CHANGE);
   // Merely need to detach the interrupt function from the pin
diff --git a/src/SDI12_boards.cpp b/src/SDI12_boards.cpp
index 2159eee..177da96 100644
--- a/src/SDI12_boards.cpp
+++ b/src/SDI12_boards.cpp
@@ -204,64 +204,6 @@ void SDI12Timer::resetSDI12TimerPrescale(void) {
 #endif
 
 
-// Arduino Zero other SAMD21 boards
-//
-#elif defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_ARCH_SAMD) || \
-  defined(__SAMD21G18A__) || defined(__SAMD21J18A__) || defined(__SAMD21E18A__)
-
-void SDI12Timer::configSDI12TimerPrescale(void) {
-  // Select generic clock generator 4 (Arduino core uses 0, 1, and 3.  RTCZero uses 2)
-  // Many examples use clock generator 4.. consider yourself warned!
-  // I would use a higher clock number, but some of the cores don't include them for
-  // some reason
-  REG_GCLK_GENDIV = GCLK_GENDIV_ID(4) |  // Select Generic Clock Generator 4
-    GCLK_GENDIV_DIV(3);                  // Divide the clock source by divisor 3
-  while (GCLK->STATUS.bit.SYNCBUSY) {}   // Wait for synchronization
-
-
-  // Write the generic clock generator 4 configuration
-  REG_GCLK_GENCTRL = (GCLK_GENCTRL_ID(4) |        // Select GCLK4
-                      GCLK_GENCTRL_SRC_DFLL48M |  // Select the 48MHz clock source
-                      GCLK_GENCTRL_IDC |     // Set the duty cycle to 50/50 HIGH/LOW
-                      GCLK_GENCTRL_GENEN) &  // Enable the generic clock clontrol
-    ~GCLK_GENCTRL_RUNSTDBY &                 // Do NOT run in stand by
-    ~GCLK_GENCTRL_DIVSEL;  // Divide clock source by GENDIV.DIV: 48MHz/3=16MHz
-                           // ^^ & ~ for DIVSEL because not not divided
-  while (GCLK->STATUS.bit.SYNCBUSY) {}  // Wait for synchronization
-
-  // Feed GCLK4 to TC3 (also feeds to TCC2, the two must have the same source)
-  // TC3 (and TCC2) seem to be free, so I'm using them
-  // TC4 is used by Tone, TC5 is tied to the same clock as TC4
-  // TC6 and TC7 are not available on all boards
-  REG_GCLK_CLKCTRL = GCLK_CLKCTRL_GEN_GCLK4 |  // Select Generic Clock Generator 4
-    GCLK_CLKCTRL_CLKEN |                       // Enable the generic clock generator
-    GCLK_CLKCTRL_ID_TCC2_TC3;  // Feed the Generic Clock Generator 4 to TCC2 and TC3
-  while (GCLK->STATUS.bit.SYNCBUSY) {}  // Wait for synchronization
-
-  REG_TC3_CTRLA |=
-    TC_CTRLA_PRESCALER_DIV1024 |  // Set prescaler to 1024, 16MHz/1024 = 15.625kHz
-    TC_CTRLA_WAVEGEN_NFRQ |       // Put the timer TC3 into normal frequency (NFRQ) mode
-    TC_CTRLA_MODE_COUNT8 |        // Put the timer TC3 into 8-bit mode
-    TC_CTRLA_ENABLE;              // Enable TC3
-  while (TC3->COUNT16.STATUS.bit.SYNCBUSY) {}  // Wait for synchronization
-}
-// NOT resetting the SAMD timer settings
-void SDI12Timer::resetSDI12TimerPrescale(void) {
-  // Disable TCx
-  TC3->COUNT16.CTRLA.reg &= ~TC_CTRLA_ENABLE;
-  while (TC3->COUNT16.STATUS.bit.SYNCBUSY) {}
-
-  // Reset TCx
-  TC3->COUNT16.CTRLA.reg = TC_CTRLA_SWRST;
-  while (TC3->COUNT16.STATUS.bit.SYNCBUSY) {}
-  while (TC3->COUNT16.CTRLA.bit.SWRST) {}
-
-  // Disable generic clock generator
-  REG_GCLK_GENCTRL = GCLK_GENCTRL_ID(4) &  // Select GCLK4
-    ~GCLK_GENCTRL_GENEN;                   // Disable the generic clock control
-  while (GCLK->STATUS.bit.SYNCBUSY) {}     // Wait for synchronization
-}
-
 // Espressif ESP32/ESP8266 boards
 //
 #elif defined(ESP32) || defined(ESP8266)
diff --git a/src/SDI12_boards.h b/src/SDI12_boards.h
index 686444f..45585c6 100644
--- a/src/SDI12_boards.h
+++ b/src/SDI12_boards.h
@@ -50,10 +50,6 @@ class SDI12Timer {
   /**
    * @brief Reset the processor timer prescaler to whatever it was prior to being
    * adjusted for this library.
-   *
-   * @note The prescaler is *NOT* set back to initial values for SAMD boards!  On those
-   * processors, generic clock generator 4 will remain configured for SDI-12 until it is
-   * reset outside of this library.
    */
   void resetSDI12TimerPrescale(void);
 
@@ -375,95 +371,6 @@ class SDI12Timer {
 #endif
 
 
-// Arduino Zero other SAMD21 boards
-//
-#elif defined(ARDUINO_SAMD_ZERO) || defined(ARDUINO_ARCH_SAMD) || \
-  defined(__SAMD21G18A__) || defined(__SAMD21J18A__) || defined(__SAMD21E18A__)
-
-/**
- * @brief A string description of the timer to use
- *
- * The Generic Clock controller GCLK provides nine Generic Clock Generators that can
- * provide a wide range of clock frequencies.
- *
- * Generators can be set to use different external and internal oscillators as source.
- * The clock of each Generator can be divided.  The outputs from the Generators are used
- * as sources for the Generic Clock Multiplexers, which provide the Generic Clock
- * (GCLK_PERIPHERAL) to the peripheral modules, as shown in Generic Clock Controller
- * Block Diagram.
- *
- * Features
- * - Provides Generic Clocks
- * - Wide frequency range
- * - Clock source for the generator can be changed on the fly
- *
- * The TC consists of a counter, a prescaler, compare/capture channels and control
- * logic. The counter can be set to count events, or it can be configured to count clock
- * pulses. The counter, together with the compare/capture channels, can be configured to
- * timestamp input events, allowing capture of frequency and pulse width. It can also
- * perform waveform generation, such as frequency generation and pulse-width modulation
- * (PWM).
- *
- * Features
- * - Selectable configuration
- *   – Up to five 16-bit Timer/Counters (TC) including one low-power TC, each
- * configurable as:
- *     - 8-bit TC with two compare/capture channels
- *     - 16-bit TC with two compare/capture channels
- *     - 32-bit TC with two compare/capture channels, by using two TCs
- * - Waveform generation
- *     – Frequency generation
- *     – Single-slope pulse-width modulation
- * - Input capture
- *     – Event capture
- *     – Frequency capture
- *     – Pulse-width capture
- * - One input event
- * - Interrupts/output events on:
- *     – Counter overflow/underflow
- *     – Compare match or capture
- * - Internal prescaler
- * - Can be used with DMA and to trigger DMA transactions
- */
-#define TIMER_IN_USE_STR "GCLK4-TC3"
-/**
- * @brief The c macro name for the assembly timer to use
- *
- * This signifies the register of timer/counter 3, the 8-bit count, the count value
- */
-#define TCNTX REG_TC3_COUNT8_COUNT  // Using Timer 3 with generic clock 4
-
-/**
- * @brief A string description of the prescaler in use.
- */
-#define PRESCALE_IN_USE_STR "3x1024"
-/**
- * @brief The number of "ticks" of the timer that occur within the timing of one bit at
- * the SDI-12 baud rate of 1200 bits/second.
- *
- * 48MHz / 3 pre-prescaler = 16MHz
- * 16MHz / 1024 prescaler = 15624 'ticks'/sec = 64 µs / 'tick'
- * (1 sec/1200 bits) * (1 tick/64 µs) = 13.0208 ticks/bit
- *
- * The 8-bit count rolls over after 256 ticks, 19.66 bits, or 16.38505 ms
- * (256 ticks/roll-over) * (1 bit/13.0208 ticks) = 19.66 bits
- * (256 ticks/roll-over) * (1 sec/15624 ticks) = 16.38505 milliseconds
- */
-#define TICKS_PER_BIT 13
-/**
- * @brief The number of "ticks" of the timer per SDI-12 bit, shifted by 2^10.
- *
- * 1/(13.0208 ticks/bit) * 2^10 = 78.6432
- */
-#define BITS_PER_TICK_Q10 79
-/**
- * @brief A "fudge factor" to get the Rx to work well.   It mostly works to ensure that
- * uneven tick increments get rounded up.
- *
- * @see https://github.com/SlashDevin/NeoSWSerial/pull/13
- */
-#define RX_WINDOW_FUDGE 2
-
 // Espressif ESP32/ESP8266 boards
 //
 #elif defined(ESP32) || defined(ESP8266)
-- 
2.34.1