check status for tvoc

[zer0page]

No description provided.

[divkam]

Just curious, why this change?

[zer0page]

suspect updating the offset every sample somehow interferes with the tvoc internal algorithm

[mburnshello]

let's also check the data ready status bit before sampling data. register 0x00 bit 3. pseudocode from manufacturer:
u8 *timer_routine_read_data(){
i2c_write(CCS_811_ADDRESS, STATUS_REG, i2c_buff, 0);
i2c_read(CCS_811_ADDRESS, i2c_buff, 1);
if(i2c_buff & 0x8) // check if data ready {
i2c_write(CCS_811_ADDRESS, ALG_RESULT_DATA, i2c_buff, 0); i2c_read(CCS_811_ADDRESS, i2c_buff, 4);
}
return i2c_buff; }

[zer0page]

@mburnshello
@plasticchris

[plasticchris]

this seems short; is it based on measurements or datasheet info?

[zer0page]

Didn't see anything in the spec sheet. This number is arbitrary, also don't
want to hog the semaphore for too long

On Nov 23, 2016 12:47 PM, "Chris Johnson" notifications@github.com wrote:

@plasticchris commented on this pull request.

In kitsune/i2c_cmd.c
#699 (review):

• /*
• * read status
• */
• int tries = 3;
• bool data_is_ready = false;
• while(tries-- > 0){

• b[0] = 0;
  

• (I2C_IF_Write(0x5a, b, 1, 1));
  

• memset(b,0, sizeof(b));
  

• I2C_IF_Read(0x5a, b, 1);
  

• if(b[0] & 0x08){
  

•     data_is_ready = true;
  

•     break;
  

• }
  

• vTaskDelay(1);
  

this seems short; is it based on measurements or datasheet info?

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