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https://github.com/meshcore-dev/MeshCore.git
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1948d284a0
This commit refactors the serial bridge functionality out of the `simple_repeater` example and into a more reusable, object-oriented structure. An `AbstractBridge` interface has been introduced, along with a concrete `SerialBridge` implementation. This encapsulates all the logic for packet framing, checksum calculation, and serial communication, cleaning up the main example file significantly. The `simple_repeater` example now instantiates and uses the `SerialBridge` class, resulting in better separation of concerns and improved code organization.
99 lines
2.6 KiB
C++
99 lines
2.6 KiB
C++
#include "SerialBridge.h"
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#include <HardwareSerial.h>
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#ifdef BRIDGE_OVER_SERIAL
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#define SERIAL_PKT_MAGIC 0xcafe
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struct SerialPacket {
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uint16_t magic, len, crc;
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uint8_t payload[MAX_TRANS_UNIT];
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SerialPacket() : magic(SERIAL_PKT_MAGIC), len(0), crc(0) {}
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};
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// Fletcher-16
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// https://en.wikipedia.org/wiki/Fletcher%27s_checksum
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inline static uint16_t fletcher16(const uint8_t *bytes, const size_t len) {
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uint8_t sum1 = 0, sum2 = 0;
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for (size_t i = 0; i < len; i++) {
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sum1 = (sum1 + bytes[i]) % 255;
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sum2 = (sum2 + sum1) % 255;
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}
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return (sum2 << 8) | sum1;
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};
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SerialBridge::SerialBridge(Stream& serial, mesh::PacketManager* mgr) : _serial(&serial), _mgr(mgr) {}
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void SerialBridge::begin() {
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#if defined(ESP32)
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((HardwareSerial*)_serial)->setPins(BRIDGE_OVER_SERIAL_RX, BRIDGE_OVER_SERIAL_TX);
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#elif defined(RP2040_PLATFORM)
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((HardwareSerial*)_serial)->setRX(BRIDGE_OVER_SERIAL_RX);
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((HardwareSerial*)_serial)->setTX(BRIDGE_OVER_SERIAL_TX);
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#elif defined(STM32_PLATFORM)
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((HardwareSerial*)_serial)->setRx(BRIDGE_OVER_SERIAL_RX);
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((HardwareSerial*)_serial)->setTx(BRIDGE_OVER_SERIAL_TX);
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#else
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#error SerialBridge was not tested on the current platform
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#endif
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((HardwareSerial*)_serial)->begin(115200);
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}
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void SerialBridge::onPacketTransmitted(mesh::Packet* packet) {
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SerialPacket spkt;
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spkt.len = packet->writeTo(spkt.payload);
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spkt.crc = fletcher16(spkt.payload, spkt.len);
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_serial->write((uint8_t *)&spkt, sizeof(SerialPacket));
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}
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void SerialBridge::loop() {
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while (_serial->available()) {
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onPacketReceived();
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}
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}
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void SerialBridge::onPacketReceived() {
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static constexpr uint16_t size = sizeof(SerialPacket) + 1;
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static uint8_t buffer[size];
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static uint16_t tail = 0;
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buffer[tail] = (uint8_t)_serial->read();
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tail = (tail + 1) % size;
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// Check for complete packet by looking back to where the magic number should be
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const uint16_t head = (tail - sizeof(SerialPacket) + size) % size;
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if ((buffer[head] | (buffer[(head + 1) % size] << 8)) != SERIAL_PKT_MAGIC) {
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return;
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}
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uint8_t bytes[MAX_TRANS_UNIT];
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const uint16_t len = buffer[(head + 2) % size] | (buffer[(head + 3) % size] << 8);
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if (len == 0 || len > sizeof(bytes)) {
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return;
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}
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for (size_t i = 0; i < len; i++) {
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bytes[i] = buffer[(head + 6 + i) % size];
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}
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const uint16_t crc = buffer[(head + 4) % size] | (buffer[(head + 5) % size] << 8);
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const uint16_t f16 = fletcher16(bytes, len);
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if ((f16 != crc)) {
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return;
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}
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mesh::Packet *new_pkt = _mgr->allocNew();
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if (new_pkt == NULL) {
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return;
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}
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new_pkt->readFrom(bytes, len);
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_mgr->queueInbound(new_pkt, 0);
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}
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#endif
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