sr_4021.h

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#pragma once
#ifndef DEV_SR_4021_H
#define DEV_SR_4021_H
#include "per/gpio.h"
#include "sys/system.h"
 
namespace daisy
{
template <size_t num_daisychained = 1, size_t num_parallel = 1>
class ShiftRegister4021
{
  public:
    struct Config
    {
        dsy_gpio_pin clk;   
        dsy_gpio_pin latch; 
        dsy_gpio_pin data[num_parallel]; 
    };
 
    ShiftRegister4021() {}
    ~ShiftRegister4021() {}
 
    void Init(const Config& cfg)
    {
        config_ = cfg;
        // Init GPIO
        clk_.mode = DSY_GPIO_MODE_OUTPUT_PP;
        clk_.pull = DSY_GPIO_NOPULL;
        clk_.pin  = cfg.clk;
        dsy_gpio_init(&clk_);
        latch_.mode = DSY_GPIO_MODE_OUTPUT_PP;
        latch_.pull = DSY_GPIO_NOPULL;
        latch_.pin  = cfg.latch;
        dsy_gpio_init(&latch_);
        for(size_t i = 0; i < num_parallel; i++)
        {
            data_[i].mode = DSY_GPIO_MODE_INPUT;
            data_[i].pull = DSY_GPIO_NOPULL;
            data_[i].pin  = cfg.data[i];
            dsy_gpio_init(&data_[i]);
        }
        // Init States
        for(size_t i = 0; i < kTotalStates; i++)
        {
            states_[i] = false;
        }
    }
 
    void Update()
    {
        dsy_gpio_write(&clk_, 0);
        dsy_gpio_write(&latch_, 1);
        System::DelayTicks(1);
        dsy_gpio_write(&latch_, 0);
        uint32_t idx;
        for(size_t i = 0; i < 8 * num_daisychained; i++)
        {
            dsy_gpio_write(&clk_, 0);
            System::DelayTicks(1);
            for(size_t j = 0; j < num_parallel; j++)
            {
                idx = (8 * num_daisychained - 1) - i;
                idx += (8 * num_daisychained * j);
                states_[idx] = dsy_gpio_read(&data_[j]);
            }
            dsy_gpio_write(&clk_, 1);
            System::DelayTicks(1);
        }
    }
 
    inline bool State(int index) const { return states_[index]; }
 
    inline const Config& GetConfig() const { return config_; }
 
  private:
    static constexpr int kTotalStates = 8 * num_daisychained * num_parallel;
    Config               config_;
    bool                 states_[kTotalStates];
    dsy_gpio             clk_;
    dsy_gpio             latch_;
    dsy_gpio             data_[num_parallel];
};
 
} // namespace daisy
 
#endif