#include "header.h"

// status codes :
// -- Master --
// TW_BUS_ERROR				0x00 = 0b0 = 0			-> illegal start or stop condition
// TW_START					0x08 = 0b1000 = 8		-> start condition transmitted
// TW_REP_START				0x10 = 0b10000 = 16		-> repeated start condition transmitted
// -- Master Transmitter --
// TW_MT_SLA_ACK			0x18 = 0b11000 = 24		-> SLA+W transmitted, ACK received
// TW_MT_SLA_NACK			0x20 = 0b100000 = 32	-> SLA+W transmitted, NACK received
// TW_MT_DATA_ACK			0x28 = 0b101000 = 40	-> data transmitted, ACK received
// TW_MT_DATA_NACK			0x30 = 0b110000 = 48	-> data transmitted, NACK received
// TW_MT_ARB_LOST			0x38 = 0b111000 = 56	-> arbitration lost in SLA+W or data
// -- Master Receiver --
// TW_MR_ARB_LOST			0x38 = 0b111000 = 56	-> arbitration lost in SLA+R or NACK
// TW_MR_SLA_ACK			0x40 = 0b1000000 = 64	-> SLA+R transmitted, ACK received
// TW_MR_SLA_NACK			0x48 = 0b1001000 = 72	-> SLA+R transmitted, NACK received
// TW_MR_DATA_ACK			0x50 = 0b1010000 = 80	-> data received, ACK returned
// TW_MR_DATA_NACK			0x58 = 0b1011000 = 88	-> data received, NACK returned
// TW_SR_GCALL_DATA_NACK	0x98 = 0b10011000 = 152 -> general call data received, NACK returned
// TW_ST_SLA_ACK			0xA8 = 0b10101000 = 168	-> SLA+R received, ACK returned
// TW_NO_INFO				0xF8 = 0b11111000 = 248	-> no state information available

#define AHT20_ADDRESS		0x38								// doc AHT20, 7.3 : address of thermistor : 0b111000, 56

void print_hex_value(char c) {
	char buffer[3] = {0};
	int_to_hex_string(c, buffer, 2);
	uart_printstr(buffer);
}

void print_data() {
	uint8_t data;
	for (uint8_t i = 0; i < 7; i++) {							// doc AHT20, 7.4 : >= 7 bytes -> CRC (Cyclic Redundancy Check), an error-detecting code
		data = i2c_read_nack();
		print_hex_value(data);
		if (i == 0) {
			uart_tx('(');
			uart_printstr_itoa_base(data, 2);
			uart_tx(')');
		}
		if (i < 9) {
			uart_tx(' ');
		}
	}
	uart_printstr_endl("");
}

Boolean aht20_is_status_ready(void) {
    uint8_t status;

    // i2c_start();
    // i2c_send_addr_w(AHT20_ADDRESS);
	// i2c_write(0xAC);
	// i2c_write(0x33);
	// i2c_write(0x00);
    i2c_start_repeat();
    i2c_send_addr_r(AHT20_ADDRESS);							// AHT20 doc 7.4 : "get a byte of status word by sending 0x71" -> SLA+R == 0x71
    status = i2c_read_nack();
    i2c_stop();

	uart_printstr("- status : ");
	uart_printstr_itoa_base_endl(status, 2);
	if (status & 0b10000000) {
	// if ((status & 0x18) != 0x18) {						// AHT20 doc 7.4 : "If the status word and 0x18 are not equal to 0x18 ..., if they are equal proceed to the next step"
		return FALSE;
	} else {
    	return TRUE;
	}
}

void aht20_wait_for_status() {
	for (uint8_t i = 0; i < 30; i++) {
		uart_tx('|');
		if (aht20_is_status_ready()) {
			break;
		}
		_delay_ms(50);
	}
}

// description
int main() {
	uart_init();
	uart_printstr("\r\n");

	// 0x18 : 11000    : 24
	// 0x33 : 110011   : 51	-> DATA0
	// 0x38 : 111000   : 56
	// 0x70 : 1110000  : 112	-> SLA+W
	// 0x71 : 1110001  : 113	-> SLA+R
	// 0x80 : 10000000 : 128
	//
	// doc AHT20 7.4 : trigger measurement data and read temperature and humidity
	//   0. init i2c
	//   1. after power on, wait >= 100ms
	//   2. send SLA+W 0x70
	//   3. wait 10ms
	//   4. send 0xAC command (172, 0b10101100) (trigger measurement), this command parameter has 2 bytes :
	//   5.   send DATA0 : 0x33
	//   6.   send DATA1 : 0x00
	//   7. delay >= 80ms (wait for status[7] == 0)
	//   8. send SLA+R
	//   9. read 6 bytes
	//   10. read CRC

	i2c_init();
	i2c_start();

	_delay_ms(200);
	// aht20_wait_for_status();


	// while(1) {
	for (uint8_t i = 0; i < 6; i++) {
		i2c_start_repeat();
		i2c_send_addr_w(AHT20_ADDRESS);

		_delay_ms(10);
		// aht20_wait_for_status();

		i2c_write(0xAC);
		i2c_write(0x33);
		i2c_write(0x00);

		aht20_wait_for_status();

		i2c_start_repeat();
		i2c_send_addr_r(AHT20_ADDRESS);

		print_data();
	}

}