Arduino TWI to NRF52 TWI conversion

RE: Arduino TWI to NRF52 TWI conversion

alexSvarc — Mon, 18 Feb 2019 06:30:57 GMT

you were totally correct even in your first reply but i was unable to understand you because of my limited knowledge...

after reading the sensor datasheet and the twi sdk documentation for more than 100 times after your reply i finally got it what i need to do... the deal was as you said i should have read all 9 bytes at once and then store the result 3 bytes at a time into the value holders of the 3 separate measurement values...

thanks allot for you help

RE: Arduino TWI to NRF52 TWI conversion

Nguyen Hoan Hoang — Wed, 13 Feb 2019 03:26:11 GMT

if you want to read 9 bytes, then you need to read it in 1 shot.

RE: Arduino TWI to NRF52 TWI conversion

alexSvarc — Tue, 12 Feb 2019 22:00:09 GMT

Thanks for your replay.
That worked somewhat.

Using a red paper over the sensor this is what i get from nrf52 board:

<info> app: Red: 69110   IR: 69101   Green: 69087
<info> app: Red: 69090   IR: 69095   Green: 69076
<info> app: Red: 69036   IR: 69061   Green: 69068
<info> app: Red: 69052   IR: 69052   Green: 69066
<info> app: Red: 69039   IR: 69047   Green: 69048
<info> app: Red: 69003   IR: 69022   Green: 69031
<info> app: Red: 69055   IR: 69040   Green: 69018
<info> app: Red: 69035   IR: 69037   Green: 69037
<info> app: Red: 69056   IR: 69077   Green: 69023
<info> app: Red: 69081   IR: 68991   Green: 69016
<info> app: Red: 69049   IR: 69022   Green: 69011
<info> app: Red: 69019   IR: 68981   Green: 68992
<info> app: Red: 68934   IR: 68948   Green: 68968
<info> app: Red: 68951   IR: 68946   Green: 68980

This is using the same red paper over the sensor from Arduino:

R[72284] IR[82808] G[1303]
R[72278] IR[82796] G[1305]
R[72280] IR[82803] G[1309]
R[72287] IR[82812] G[1306]
R[72282] IR[82819] G[1317]
R[72270] IR[82819] G[1311]
R[72276] IR[82813] G[1315]
R[72283] IR[82823] G[1309]
R[72286] IR[82825] G[1303]
R[72287] IR[82821] G[1309]
R[72289] IR[82828] G[1306]
R[72291] IR[82815] G[1308]
R[72280] IR[82805] G[1306]
R[72299] IR[82818] G[1305]
R[72298] IR[82818] G[1315]
R[72289] IR[82819] G[1306]
R[72308] IR[82826] G[1307]
R[72310] IR[82809] G[1303]

RE: Arduino TWI to NRF52 TWI conversion

Nguyen Hoan Hoang — Tue, 12 Feb 2019 17:39:22 GMT

I guess what you wanted to do is :

uint8_t m_sample[sizeof(toGet)];      
      while (toGet > 0)
      {
        sense.head++; //Advance the head of the storage struct
        sense.head %= MAX30105_STORAGE_SIZE; //Wrap condition

        uint8_t temp[sizeof(uint32_t)]; //Array of 4 uint8_ts that we will convert into long
        uint32_t tempLong;

        //Burst read three uint8_ts - RED
        err_code1 = nrf_drv_twi_rx(&m_twi, MAX30105_ADDRESS, temp, 3);                
        APP_ERROR_CHECK(err_code1);
        templong = ((uint32_t)temp[0] << 16) | ((uint32_t)temp[1]<<8) | temp[2];
        
      }