//////////////////////////////////////////////////////////////////////////////////////////
//
//  Protocentral ADS1293 Arduino example — 5-lead ECG (OpenView packet format)
//
//  Author: Ashwin Whitchurch, Protocentral Electronics
//  SPDX-FileCopyrightText: 2025 Protocentral Electronics
//  SPDX-License-Identifier: MIT
//
//  Streams ECG samples in the OpenView packet format. See the OpenView
//  project for the host-side processing tools:
//    https://github.com/Protocentral/protocentral_openview
//
//  Hardware connections (Arduino UNO / ESP32 VSPI):
//
//  | Signal | Arduino UNO | ESP32 (VSPI default) |
//  |-------:|:-----------:|:--------------------:|
//  | MISO   | 12          | 19                   |
//  | MOSI   | 11          | 23                   |
//  | SCLK   | 13          | 18                   |
//  | CS     | 4           | 4                    |
//  | VCC    | +5V         | +5V                  |
//  | GND    | GND         | GND                  |
//  | DRDY   | 2           | 2                    |
//
//  For full documentation and examples, see:
//    https://github.com/Protocentral/protocentral-ads1293-arduino
//
/////////////////////////////////////////////////////////////////////////////////////////


#include "protocentral_ads1293.h"
#include <SPI.h>

#define CES_CMDIF_PKT_START_1 0x0A
#define CES_CMDIF_PKT_START_2 0xFA
#define CES_CMDIF_TYPE_DATA 0x02
#define CES_CMDIF_PKT_STOP 0x0B
#define DATA_LEN 12
#define ZERO 0

#define DRDY_PIN 2
#define CS_PIN 4

// Uncomment to send voltages instead of raw ADC codes
// #define PRINT_VOLTAGE

// Optional SPI pin overrides
#if !defined(SCK_PIN)
#if defined(ARDUINO_ARCH_ESP32)
#define SCK_PIN 18
#define MISO_PIN 19
#define MOSI_PIN 23
#else
#define SCK_PIN 13
#define MISO_PIN 12
#define MOSI_PIN 11
#endif
#endif

ads1293 ADS1293(DRDY_PIN, CS_PIN);

volatile uint8_t DataPacket[DATA_LEN];
const uint8_t DataPacketFooter[2] = {ZERO, CES_CMDIF_PKT_STOP};
const uint8_t DataPacketHeader[5] = {CES_CMDIF_PKT_START_1, CES_CMDIF_PKT_START_2, DATA_LEN, ZERO, CES_CMDIF_TYPE_DATA};

void sendDataThroughUart(int32_t ecgCh1, int32_t ecgCh2, int32_t ecgCh3) {
	// pack little-endian 32-bit values
	DataPacket[0] = static_cast<uint8_t>(ecgCh1 & 0xFF);
	DataPacket[1] = static_cast<uint8_t>((ecgCh1 >> 8) & 0xFF);
	DataPacket[2] = static_cast<uint8_t>((ecgCh1 >> 16) & 0xFF);
	DataPacket[3] = static_cast<uint8_t>((ecgCh1 >> 24) & 0xFF);

	DataPacket[4] = static_cast<uint8_t>(ecgCh2 & 0xFF);
	DataPacket[5] = static_cast<uint8_t>((ecgCh2 >> 8) & 0xFF);
	DataPacket[6] = static_cast<uint8_t>((ecgCh2 >> 16) & 0xFF);
	DataPacket[7] = static_cast<uint8_t>((ecgCh2 >> 24) & 0xFF);

	DataPacket[8] = static_cast<uint8_t>(ecgCh3 & 0xFF);
	DataPacket[9] = static_cast<uint8_t>((ecgCh3 >> 8) & 0xFF);
	DataPacket[10] = static_cast<uint8_t>((ecgCh3 >> 16) & 0xFF);
	DataPacket[11] = static_cast<uint8_t>((ecgCh3 >> 24) & 0xFF);

	// send packet header
	for (int i = 0; i < 5; ++i) {
		Serial.write(DataPacketHeader[i]);
	}

	// send actual data
	for (int i = 0; i < DATA_LEN; ++i) {
		Serial.write(DataPacket[i]);
	}

	// send packet footer
	for (int i = 0; i < 2; ++i) {
		Serial.write(DataPacketFooter[i]);
	}
}

// Helper: convert 24-bit unsigned raw value to signed 32-bit using two's-complement
static int32_t raw24_to_int24(uint32_t raw24) {
	raw24 &= 0xFFFFFFu;
	if (raw24 & 0x800000u) {
		return static_cast<int32_t>(raw24 | 0xFF000000u);
	}
	return static_cast<int32_t>(raw24);
}

// Helper: build a 24-bit raw value from three bytes (MSB, mid, LSB)
static uint32_t raw24_from_bytes(uint8_t msb, uint8_t mid, uint8_t lsb) {
	return (static_cast<uint32_t>(msb) << 16) | (static_cast<uint32_t>(mid) << 8) | static_cast<uint32_t>(lsb);
}

// Uncomment to enable debug register/sample dumps on startup
// #define ENABLE_DEBUG

void setup() {
	Serial.begin(57600);
#if defined(ARDUINO_ARCH_ESP32)
	ADS1293.begin(SCK_PIN, MISO_PIN, MOSI_PIN);
#else
	ADS1293.begin();
#endif
	// Configure device for 5-lead ECG using explicit helpers
	ADS1293.configureChannel1(FlexCh1Mode::Default);
	ADS1293.configureChannel2(FlexCh2Mode::Default);
	ADS1293.configureChannel3(FlexCh3Mode::Default);
	ADS1293.enableCommonModeDetection(CMDetMode::Enabled);
	ADS1293.configureRLD(RLDMode::Default);
	ADS1293.configureRef(RefMode::Default);
	ADS1293.configureOscillator(OscMode::Default);
	ADS1293.configureAFEShutdown(AFEShutdownMode::AFE_On);

	ADS1293.setSamplingRate(ADS1293::SamplingRate::SPS_100);
	ADS1293.setChannelGain(1, ADS1293::PgaGain::G8);
	ADS1293.setChannelGain(2, ADS1293::PgaGain::G8);
	ADS1293.setChannelGain(3, ADS1293::PgaGain::G8);
	ADS1293.configureDRDYSource(DRDYSource::Default);
	ADS1293.configureChannelConfig(ChannelConfig::Default5Lead);
	ADS1293.applyGlobalConfig(GlobalConfig::Start);
	delay(10);

#if defined(ENABLE_DEBUG)
	ADS1293.dumpDebug(Serial);
#endif
}

void loop() {
	if (digitalRead(DRDY_PIN) == LOW) {
		// Use convenience overload to get all three channels in one call
		auto samples = ADS1293.getECGData();
		if (samples.ok) {
				// Read raw 24-bit values from the device, sign-extend to int32_t,
				// and send as 32-bit little-endian (LSB first) in the packet payload.
				uint32_t raw1 = 0, raw2 = 0, raw3 = 0;
				if (ADS1293.getRaw24(1, raw1) && ADS1293.getRaw24(2, raw2) && ADS1293.getRaw24(3, raw3)) {
					int32_t s1 = raw24_to_int24(raw1);
					int32_t s2 = raw24_to_int24(raw2);
					int32_t s3 = raw24_to_int24(raw3);
					sendDataThroughUart(s1, s2, s3);
				}
		}
	}
	delay(10);
}

