rmt_item_types.hpp

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/*
 * SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
 *
 * SPDX-License-Identifier: MIT
 */
#ifndef M5_UNIT_RF433_RMT_ITEM_TYPES_HPP
#define M5_UNIT_RF433_RMT_ITEM_TYPES_HPP
 
#include <M5UnitComponent.hpp>
#if defined(ESP_PLATFORM)
#include <soc/soc_caps.h>
#endif
 
namespace m5 {
namespace unit {
namespace rf433 {
 
constexpr m5::unit::gpio::m5_rmt_item_t rmt_item_one{{800, 1, 200, 0}};   // 1
constexpr m5::unit::gpio::m5_rmt_item_t rmt_item_zero{{200, 1, 800, 0}};  // 0
constexpr m5::unit::gpio::m5_rmt_item_t rmt_sof_0{{4868, 1, 2469, 0}};    // Frame start 0
constexpr m5::unit::gpio::m5_rmt_item_t rmt_sof_1{{1647, 1, 315, 0}};     // Frame start 1
constexpr m5::unit::gpio::m5_rmt_item_t rmt_preamble{{500, 1, 500, 0}};   // preamble
 
using container_type             = std::vector<uint8_t>;              
using item_container_type        = std::vector<gpio::m5_rmt_item_t>;  
using communication_identifier_t = uint8_t;                           
 
constexpr uint8_t ProtocolOverhead = 4;
 
#if defined(M5_UNIT_UNIFIED_USING_RMT_V2)
constexpr uint8_t RmtRxMemBlocks = 2;
#elif defined(SOC_RMT_SUPPORT_RX_PINGPONG) && SOC_RMT_SUPPORT_RX_PINGPONG
constexpr uint8_t RmtRxMemBlocks = 1;
#elif defined(SOC_RMT_RX_CANDIDATES_PER_GROUP)
// RX channels are the last SOC_RMT_RX_CANDIDATES_PER_GROUP ones and their blocks must stay within the group
constexpr uint8_t RmtRxMemBlocks = (SOC_RMT_RX_CANDIDATES_PER_GROUP < 6) ? SOC_RMT_RX_CANDIDATES_PER_GROUP : 6;
#else
constexpr uint8_t RmtRxMemBlocks = 6;  // Host (native) build: same as ESP32
#endif
 
#if defined(M5_UNIT_UNIFIED_USING_RMT_V2)
constexpr uint16_t RmtRxMaxItems = 4096;  // RMT v2: ping-pong/DMA handles large frames
#elif defined(SOC_RMT_MEM_WORDS_PER_CHANNEL)
constexpr uint16_t RmtRxMaxItems =
    RmtRxMemBlocks * SOC_RMT_MEM_WORDS_PER_CHANNEL;  // ESP32: 384, ESP32-S2: 256, ESP32-S3 / ESP32-C3: 48
#else
constexpr uint16_t RmtRxMaxItems = RmtRxMemBlocks * 64;  // Host (native) build: same as ESP32
#endif
 
constexpr uint8_t MaxPayloadSize =
#if defined(M5_UNIT_UNIFIED_USING_RMT_V2)
    255;
#elif defined(SOC_RMT_SUPPORT_RX_PINGPONG) && SOC_RMT_SUPPORT_RX_PINGPONG
    // ESP32-S3 / ESP32-C3 use mem_blocks=1 with threshold ISR wrapping;
    // theoretical limit depends on ISR throughput, use ESP32 equivalent
    43;
#else
    static_cast<uint8_t>((RmtRxMaxItems - 1 /*SOF*/) / 8 - ProtocolOverhead);
#endif
 
constexpr uint32_t calculateRingBufferSize(const uint32_t payload_size)
{
    // Frame: SOF(1 item) + (overhead + payload) * 8 Manchester items per byte
    return (1 /*SOF*/ + (ProtocolOverhead + payload_size) * 8) * sizeof(m5::unit::gpio::m5_rmt_item_t) +
           2 /*length prefix*/;
}
 
item_container_type encodeManchester(const uint8_t* data, const uint32_t len, const bool MSB = true);
 
uint16_t decodeManchester(uint8_t* buf, const uint16_t buf_size, const m5::unit::gpio::m5_rmt_item_t* data,
                          const uint32_t num, const bool MSB = true);
 
}  // namespace rf433
}  // namespace unit
}  // namespace m5
#endif