Migrating ADS1015 from Wire about brzo_i2c HOT 5 CLOSED

I suspect some timing issues while reading from the slave during/after ADC.

According to the datasheet it is also possible to read from the config register. Thus, could try to write to the config register value x and read it back? And repeat this with a value y? If you get different values back, i.e. x and y then the basic i2c communication is fine and we have to look deeper at the ADC part.

from brzo_i2c.

Thanks, have tried reading back the config register now.
Results are positive with Wire library: value written can be immediately read back with no issues.

With bgzo_i2c, however, value received back after writing does not match the one I've attempted to write.
Moreover, in the following sequence:

• Flash Wire example
• Write config register with value X, read back, confirm it's the same.
• Without powering down ADS1015, flash brzo_i2c example into the ESP
• Write value Y to the config register
• Read it back

I am actually receiving back value X, which has been written previously with Wire example.

So I assume, brzo_i2c can read data. But it's having issues writing 2-byte config register.

from brzo_i2c.

I had a closer look at the datasheet. Figure 17 shows the expected i2c communication:

In other words:

i. START
ii. Slave Address
iii. Send Pointer Register (1 Byte)
iv. Send Data (here in the example 2 Bytes)
v. STOP

However, what you are sending is:

1. START
2. Slave Address
3. Pointer Register (1 Byte)
   (NO STOP)
4. (REPEATED) START
5. Slave Address
6. Data (2 Bytes)
7. STOP

In your code brzo_i2c_write(buffer,1, true); corresponds to 1., 2., 3. then brzo_i2c_write(buffer,2,false); corresponds to 4., 5., 6., 7.

Note that the wire library behaves differently, see the wiki.

That's why the wire library code works.

So, what you need to do is:

• Use a buffer of three bytes
• Put all the data (Pointer Register and the bytes for config register) in the buffer
• Send it all together, i.e. call brzo_i2c_write(buffer,3,false);

from brzo_i2c.

Thanks a lot, the following actually works:

    uint8_t buffer[3];
    brzo_i2c_start_transaction(ADS1X15_ADDRESS, BRZO_I2C_SPEED);
    buffer[0] = 1;
    buffer[1] = (uint8_t)(cfg_value >> 8);
    buffer[2] = (uint8_t)(cfg_value & 0xFF);
    brzo_i2c_write(buffer,3,false);

    rc = brzo_i2c_end_transaction();

from brzo_i2c.

You are welcome. I've updated the wiki on how to migrate from Wire Library to brzo, I hope it is better explained now.

from brzo_i2c.