RRH62000 Sleep/wakeup, CRC

Question

Hello, 
 
 I'm connecting the sensor through I2C - I can read correct data frame if it's awake all the time. 
 What sequence is required in this case? This code, for example, does not work - received frame has invalid data (even if I keep reading them for some time): 
 #define RRH62000_I2C_SDA D1
#define RRH62000_I2C_SCL D2
#define RRH62000_I2C_ADDR 0x69
#define RRH62000_I2C_FRAME_BYTES 37

void setup()
{
 ...
 Wire.begin(RRH62000_I2C_SDA, RRH62000_I2C_SCL, RRH62000_I2C_ADDR);
 ...
}

void loop()
{
 Wire.beginTransmission(RRH62000_I2C_ADDR);
 Wire.write(0x50); Wire.write(0x80); // WAKE-UP
 Wire.endTransmission();
 
 delay(1000); // wait some time

unsigned char index = 0;
 Wire.requestFrom(RRH62000_I2C_ADDR, RRH62000_I2C_FRAME_BYTES);
 while(Wire.available())
 {
 RRH62000_Frame[index] = Wire.read();
 index++;
 }
 
 RRH62000_Frame_Temperature = ((RRH62000_Frame[24] << 8) | RRH62000_Frame[25]) * 0.01;
 ...
 
 Wire.beginTransmission(RRH62000_I2C_ADDR);
 Wire.write(0x50); Wire.write(0); // SLEEP
 Wire.endTransmission();
 
 delay(1000); // wait some time
} 
 The result: 
 
 RRH62000 Frame: 0:FF 1:FF 2:A 3:3 4:E8 5:3 6:E8 7:FF 8:FF 9:4E 10:C0 11:A 12:19 13:17 14:A6 15:A6 16:A6 17:A6 18:A6 19:A6 20:A6 21:A6 22:A6 23:A6 24:A6 25:A6 26:A6 27:A6 28:A6 29:A6 30:A6 31:A6 32:A6 33:A6 34:A6 35:A6 36:A6

Without sleep/wake-up I get the following:

RRH62000 Frame: 0:0 1:0 2:0 3:A6 4:0 5:39 6:0 7:E 8:0 9:1 10:0 11:0 12:0 13:1C 14:0 15:75 16:0 17:BA 18:0 19:3C 20:0 21:3F 22:0 23:3F 24:9 25:F1 26:19 27:A1 28:0 29:2 30:1 31:90 32:0 33:64 34:0 35:0 36:45 
Temperature:25.5C
Humidity:65.6%
PM1:2.8ug/m3
PM2.5:11.7ug/m3
PM10:18.6ug/m3
TVOC:20ug/m3
eCO2:400ppm

Next question, do you have a C code for generating the CRC checksum? 
 Thank you very much!

IK_Renesas · Accepted Answer

Hello, 
 As far I can understand your requirement is to be able to put the sensor to sleep and wake-up whenever you want to take a measurement. 
 Yes unfortunately the code from the middleware in the project I provided you does not have this functionality. 
 Since in the middleware sleep command is not supported and has not been implemented yet. 
 
 It will be added in the next releases. 
 However let me check this also internally to see if there is something you should specifically do and follow after waking-up the sensor. Since in the datasheet of the sensor nothing is mentioned about it. 
 Something else I would like to point out is that in your code you attached before requesting to read this 37 bytes you do not send the read command as mentioned in the commands of the datasheet.

So the sequence should be like this: 
 1. Wake up the sensor by sending through I2C bus 2 bytes (0x50,0x80) 
 2.Wait 
 3. Send command 0x00.Read command 
 4. Request to read 37 bytes . 
 5. Go to sleep by sending through I2C bus 2 bytes (0x50,0x00). 
 
 Best Regards, 
 IK

damo · Answer

Hello, 
 sorry for the delay. 
 IK_Renesas said: Send command 0x00.Read command 
 This solves the problem, thank you very much! 
 Regards, 
 Damjan

IK_Renesas · Answer

Hello, 
 Thanks for reaching out Renesas Engineering Community. 
 Unfortunattely there is no sample code published yet for I2C communication for RRH62000 sensor. 
 However we provide a middleware which you can maybe take as reference for our RA MCU Family and FSP 5.6.0. 
 I will share with you a project to see the code and the basic operation for I2C communication with the specific sensor. 
 
 Regarding calculating the checksum there is also a function implemented in the code I will share with you the 
 rm_rrh62000_crc_execute. 
 The code for calculating the checksum should look like this: 
 void rrh62000_crc_execute (void)
{
 uint8_t crc;
 uint8_t i;
 uint8_t j;
 
 /*Set initial value*/
 crc = 0xFF;
 for ( i =0; i<36; i++)
 {
 crc = raw_data[i];
 for(j=0;j<8;j++)
 {
 if(0x80 == (crc &0x80))
 {
 /* If MSB is 1, calculate XOR with the polynomial. */
 crc = (uint8_t) (crc <<1) ^ 0x31;
 
 }
 else
 {
 crc << =1;
 
 }
 }
 
 }
 /*Final XOR*/
 crc ^ = 0x00;
 
 if (crc == raw_data[36])
 {
 printf("Correct crc-Valid Data 
");
 }
 
 else
 {
 printf("Invalid data 
");
 }
 
} 
 RA4M2_RRH.zip 
 
 Hope it helps. 
 
 BR, 
 IK

RRH62000 Sleep/wakeup, CRC

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