MC146818.h

/*
  Created by Fabrizio Di Vittorio (fdivitto2013@gmail.com) - <http://www.fabgl.com>
  Copyright (c) 2019-2022 Fabrizio Di Vittorio.
  All rights reserved.
 
 
* Please contact fdivitto2013@gmail.com if you need a commercial license.
 
 
* This library and related software is available under GPL v3.
 
  FabGL 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.
 
  FabGL 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 FabGL.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 
#pragma once
 
 
#include "nvs_flash.h"
#include "nvs.h"
#include "esp_timer.h"
 
#include "fabgl.h"
 
 
#if FABGL_ESP_IDF_VERSION <= FABGL_ESP_IDF_VERSION_VAL(3, 3, 5)
typedef nvs_handle nvs_handle_t;
#endif
 
 
namespace fabgl {
 
 
// RTC MC146818 emulator
 
// On the PC/AT there are following connections:
//    /IRQ   -> IRQ8 (INT 70h)
//    CKFS   -> 5V  (hence CKOUT has the same frequency as OSC1)
//    PS     -> 5V
//    /RESET -> 5V
//    OSC1   -> 32768Hz clock
//    OSC2   -> NC
//    CKOUT  -> NC
//    SQW    -> NC
 
// I/O Access
//   port 0x70 (W)   : Register address port (bits 0-6)
//   port 0x71 (R/W) : Register read or write
 
 
class MC146818 {
 
public:
 
  typedef bool (*InterruptCallback)(void * context);
 
  MC146818();
  ~MC146818();
 
  void init(char const * NVSNameSpace);
 
  void setCallbacks(void * context, InterruptCallback interruptCallback) {
    m_context           = context;
    m_interruptCallback = interruptCallback;
  }
 
  void reset();
 
  void commit();
 
  uint8_t read(int address);
  void write(int address, uint8_t value);
 
  uint8_t & reg(int address) { return m_regs[address]; }
 
  void updateTime();
 
private:
 
  void enableTimers();
 
  void stopPeriodicTimer();
  void stopEndUpdateTimer();
 
  static void periodIntTimerFunc(void * args);
  static void endUpdateIntTimerFunc(void * args);
 
 
  nvs_handle_t       m_nvs;
 
  uint8_t            m_regs[64];
  uint8_t            m_regSel;
 
  void *             m_context;
  InterruptCallback  m_interruptCallback;
 
  esp_timer_handle_t m_periodicIntTimerHandle;
  esp_timer_handle_t m_endUpdateIntTimerHandle;
 
};
 
 
 
 
 
 
 
}   // fabgl namespace