Add allwinner h3 support

CMakeLists.txt

@@ -21,7 +21,7 @@ set(INCLUDE_DIRS ${CMAKE_SOURCE_DIR}/include)
 set(PLATFORM_DEPENDENCIES "")
 
 # select the platform
-set(SUPPORTED_PLATFORMS rpi jetson)
+set(SUPPORTED_PLATFORMS rpi jetson sunxih3)
 set(PLATFORM "rpi" CACHE STRING "Platform")
 
 if(NOT ${PLATFORM} IN_LIST SUPPORTED_PLATFORMS)

README.md

@@ -18,14 +18,25 @@ centimeters, but **_before running this program, make sure you follow your
 local laws with regard to restrictions on radio transmissions._**
 
 ### Platform
-txtempus supports Raspberry Pi series and Nvidia Jetson Series (experimental).
+txtempus supports Raspberry Pi series, Sunxi H3 Allwinner based boards (e.g. OrangePI PC) and Nvidia Jetson Series (experimental).
 
 #### Raspberry Pi
 So far, it has been tested on a Pi3 and a
 Pi Zero W. There has been a report of different frequencies generated with
 an older Pi (Bug #1), so until we have a definitive list of available
 clock sources inside these, check out that bug for a workaround.
 
+#### SunxiH3 - OrangePI PC
+So far, it has been tested on an OrangePI PC. Any H3 based boards should work.
+The H3 has only one PWM available - PWM0. This - on the OrabgePI PC board - has
+a clock output on the 3-pin header debug UART UART0. The PWM output is the PA5 pin, connected to
+the middle pin of the debug UART. For amplitude modulation PA6 (GPIO17) is used, just as in case of thePi.
+
+One may consider using PA4 as the amplitude modulation pin- next to the PWM clock pin - but my
+experience shows that the board would not normally boot with the default settings if the antenna
+is connected to the debug UART.
+
+
 #### Nvidia Jetson Series (experimental)
 So far, it has been tested only on a Jetson Nano,
 but all Jetson devices except for TX1 and TX2 (there is no available pwm pin) are supported.
@@ -62,7 +73,7 @@ If you're in/or want to display a different time-zone, issue
 you.
 
 ### Minimal External Hardware
-#### Raspberry Pi
+#### Raspberry Pi & H3 OrangePI
 The external hardware is simple: we use the frequency output on one pin and
 another pin to pull the signal to a lower level for the regular attenuation.
 
@@ -75,7 +86,8 @@ Schematic                      | Real world
 
 
 GPIO4 and 17 are on the inner row of the Header pin, three pins inwards on
-the [Raspberry Pi GPIO]-Header.
+the [Raspberry Pi GPIO]-Header.	For the OrangePI instead of using GPIO4 connect
+the wire to PA5 - the middle pin of the 3-pin debug UART header - UART0.
 
 You don't need GPIO17 and the 560Ω resistor for `MSF`, as that works with
 switching the signal (on-off keying) instead of attenuating. In that case, you
@@ -149,6 +161,12 @@ watch/clock.
  make
 ```
 
+#### SunxiH3 - OrangePI PC
+```
+ cmake ../ -DPLATFORM=sunxih3
+ make
+```
+
 #### Nvidia Jetson Series (experimental)
 Before you build txtempus on your Jetson:
 - You should install [JetsonGPIO](https://github.com/pjueon/JetsonGPIO) which is a library that enables the use of Jetson's GPIOs.
@@ -296,4 +314,5 @@ watch holder             | ... with watch
 [MSF]: https://en.wikipedia.org/wiki/Time_from_NPL_(MSF)
 [NTP]: https://en.wikipedia.org/wiki/Network_Time_Protocol
 [Raspberry Pi GPIO]: https://www.raspberrypi.org/documentation/usage/gpio/
+[Allwinner H3 Datasheet]: https://linux-sunxi.org/H3
 [very wrong frequency]: https://github.com/hzeller/txtempus/issues/1

cmake/sunxih3-control.cmake

@@ -0,0 +1 @@
+list(APPEND SRC_FILES src/sunxih3-control.cc)

include/sunxih3/hardware-control-implementation.h

@@ -0,0 +1,98 @@
+// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
+// Part of txtempus, a Low Frequency/Long Wave time signal transmitter.
+// Copyright (C) 2022 Domokos Molnar <[email protected]>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef SUNXIH3_HARDWARE_CONTROL_IMPLEMENTATION_H
+#define SUNXIH3_HARDWARE_CONTROL_IMPLEMENTATION_H
+
+#include "hardware-control.h"
+#include <stdint.h>
+#include <stdio.h>
+#include <map>
+
+
+// -- Implementation for Allwinner H3 SOC -- https://linux-sunxi.org/Category:H3_Devices
+// Tested on OrangePI PC
+class HardwareControl::Implementation {
+ public:
+
+  // Initialize
+  bool Init();
+
+  // Set frequency output on PA5 as close as possible to the requested one.
+  // Returns the approximate frequency it could configure or -1 if that was
+  // not possible.
+  // You need to identify PA5 on your board on the OrngePI PC it is the middle pin of the debug UART
+  double StartClock(double frequency_hertz);
+  void StopClock();
+
+  // Switches the output of the currently running clock.
+  void EnableClockOutput(bool enable);
+
+  // Sets the power of the output by pulling low the voltage divider's mid point
+  void SetTxPower(CarrierPower power);
+
+ private:
+  enum TPwmCtrlReg { 
+    PWM0_RDY = 28, 
+    PWM0_BYPASS =  9, 
+    PWM_CH0_PUL_START = 8,
+    PWM_CHANNEL0_MODE = 7,
+    SCLK_CH0_GATING = 6,
+    PWM_CH0_ACT_STA = 5,
+    PWM_CH0_EN = 4,
+    PWM_CH0_PRESCAL = 0 };
+
+  enum TPwmCh0Period {
+    PWM_CH0_ENTIRE_CYS = 16, 
+    PWM_CH0_ENTIRE_ACT_CYS = 0 };
+
+  // PWM clock presaclers
+  std::map<int, int>PwmCh0Prescale;
+
+  // PA6 and PA5 pins are used
+  enum gpio_pin {
+      PA5,
+      PA6
+      };
+
+  struct pwm_params {
+      int period;
+      int prescale;
+      double frequency;
+      };
+
+  // Registers of the board
+  volatile uint32_t *registers = nullptr;
+
+  uint32_t *map_register(off_t register_offset);
+
+  // Setup pin as output or LOW-Z input
+  void SetOutput(gpio_pin pin);
+  void SetInput(gpio_pin pin);
+
+  // Configure pins
+  void ConfigurePins(void);
+
+  // Calculate PWM parameters based on requested output frequency
+  pwm_params CalculatePWMParams(double requested_freq);
+  void WaitPwmPeriodReady();
+
+};
+
+using H3BOARD = HardwareControl::Implementation;
+
+#endif // SUNXIH3_HARDWARE_CONTROL_IMPLEMENTATION_H