uart_wave_encoder.h

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#pragma once
 
#include "fl/chipsets/chipset_timing_config.h"
#include "fl/stl/compiler_control.h"
#include "fl/stl/isr/memcpy.h"
#include "fl/stl/cstddef.h"
#include "fl/stl/stdint.h"
#include "fl/stl/noexcept.h"
 
FL_OPTIMIZATION_LEVEL_O3_BEGIN
 
namespace fl {

constexpr u32 kMaxUartBaudRate = 5000000;

struct Wave10Lut {
    u8 lut[4];         
    u8 pulses_per_bit; 

    u8 dataBits() const FL_NO_EXCEPT {
        return static_cast<u8>(2 * pulses_per_bit - 2);
    }

    u32 baudRate(const ChipsetTimingConfig& timing) const FL_NO_EXCEPT {
        const u32 period_ns = timing.total_period_ns();
        if (period_ns == 0 || pulses_per_bit == 0) return 0;
        return static_cast<u32>(
            static_cast<u64>(pulses_per_bit) * 1000000000ULL / period_ns);
    }

    static u32 computeBaudRate(const ChipsetTimingConfig& timing) FL_NO_EXCEPT {
        const u32 period_ns = timing.total_period_ns();
        if (period_ns == 0) return 0;
        return static_cast<u32>(5000000000ULL / period_ns);
    }
};

Wave10Lut buildWave10Lut(const ChipsetTimingConfig& timing) FL_NO_EXCEPT;

Wave10Lut buildWave10LutForMaxBaud(const ChipsetTimingConfig& timing,
                                   u32 max_baud_rate) FL_NO_EXCEPT;

ChipsetTiming uartWireTiming(const ChipsetTimingConfig& timing,
                             u32 max_baud_rate) FL_NO_EXCEPT;

bool canRepresentTiming(const ChipsetTimingConfig& timing) FL_NO_EXCEPT;

bool canRepresentTimingForMaxBaud(const ChipsetTimingConfig& timing,
                                  u32 max_baud_rate) FL_NO_EXCEPT;
 
namespace detail {

FASTLED_FORCE_INLINE FL_IRAM FL_OPTIMIZE_FUNCTION
u8 encodeUart2Bits(u8 two_bits, const Wave10Lut& lut) FL_NO_EXCEPT {
    return lut.lut[two_bits & 0x03];
}

FASTLED_FORCE_INLINE FL_IRAM FL_OPTIMIZE_FUNCTION
void encodeUartByte(u8 led_byte, u8* output, const Wave10Lut& lut) FL_NO_EXCEPT {
    output[0] = encodeUart2Bits((led_byte >> 6) & 0x03, lut);  // Bits 7-6
    output[1] = encodeUart2Bits((led_byte >> 4) & 0x03, lut);  // Bits 5-4
    output[2] = encodeUart2Bits((led_byte >> 2) & 0x03, lut);  // Bits 3-2
    output[3] = encodeUart2Bits((led_byte >> 0) & 0x03, lut);  // Bits 1-0
}

FASTLED_FORCE_INLINE FL_IRAM FL_OPTIMIZE_FUNCTION
u8 encodeUart2Bits(u8 two_bits) FL_NO_EXCEPT {
    // Hardcoded WS2812 LUT for backward compatibility with existing tests
    static constexpr u8 kWs2812Lut[4] = {0xEF, 0x8F, 0xEC, 0x8C};
    return kWs2812Lut[two_bits & 0x03];
}

FASTLED_FORCE_INLINE FL_IRAM FL_OPTIMIZE_FUNCTION
void encodeUartByte(u8 led_byte, u8* output) FL_NO_EXCEPT {
    output[0] = encodeUart2Bits((led_byte >> 6) & 0x03);  // Bits 7-6
    output[1] = encodeUart2Bits((led_byte >> 4) & 0x03);  // Bits 5-4
    output[2] = encodeUart2Bits((led_byte >> 2) & 0x03);  // Bits 3-2
    output[3] = encodeUart2Bits((led_byte >> 0) & 0x03);  // Bits 1-0
}
 
} // namespace detail

FL_IRAM FL_OPTIMIZE_FUNCTION
size_t encodeLedsToUart(const u8* input,
                        size_t input_size,
                        u8* output,
                        size_t output_capacity,
                        const Wave10Lut& lut) FL_NO_EXCEPT;

FL_IRAM FL_OPTIMIZE_FUNCTION
size_t encodeLedsToUart(const u8* input,
                        size_t input_size,
                        u8* output,
                        size_t output_capacity) FL_NO_EXCEPT;

FASTLED_FORCE_INLINE
constexpr size_t calculateUartBufferSize(size_t input_size) FL_NO_EXCEPT {
    return input_size * 4;
}

FASTLED_FORCE_INLINE
constexpr size_t calculateUartBufferSizeForLeds(size_t num_leds) FL_NO_EXCEPT {
    return num_leds * 3 * 4;  // 12 bytes per RGB LED
}
 
} // namespace fl
 
FL_OPTIMIZATION_LEVEL_O3_END