Does the SC18IM704 UART-I2C bridge allow reading and writing to specific target device addresses?

[orbeet1973]

Hi,

I would like to read a specific register from my target device but no where in the SC18IM704 data sheet does it mention reading or writing from target device registers.  There are only 4 types of read/write commands specified (pages 4-6) and as far as I can tell they only allow me to read/write a quantity of bytes but there is no mention of reading/writing to a specific address within that target device.

To clarify my question, I want to read register 0x92 on target device (address 0111001) and conversely I would like to read several locations within that device.

Any help on this will be greatly appreciated.

Oscar

[orbeet1973]

Hi Tomas,

Thank you for taking the time to explain the syntax usage.  I was thrown off because I didn't recognize that DATA 0 actually could be used for the register address.  I will test this out shortly.

Much appreciated!

Oscar

[TomasVaverka]

Hi Oscar,

The SC18IM704 does allow to write to target device register.

Look at the example in the UM11664 (page 7):

So the register address actually corresponds to DATA 0 in Figure 3:

As for reading from a specific register, you need first to specify the register address:

Then you need to specify the number of bytes to be read starting from this address:

I hope it makes sense. 

Just to add that the 7-bit slave address of the EEPROM used on the EVB is 0x50 which translates to 0xA0 for a write and 0xA1 for a read used in these examples.

Best regards,

Tomas

[orbeet1973 · Accepted solution]

Hi Tomas,

I have tested my circuit and it works great.

Thank you for your support.

Oscar

[TomasVaverka]

Hi Oscar,

Thanks for your feedback, glad to hear it works flawlessly.

Best regards,

Tomas