Hi Abhay,
Here are the answers your questions:
[quote user="Abhay Kothari1"]When i send 0x2000 followed by 0x0000 to read config register 0 , i am receiving numbers like 0x4CFF , 0x4E00 in succesive read iterations [/quote]
When reading or writing to the ADS1259 registers, make sure you first send the SDATAC command (0x11).
The next byte, "0x2000", indicates that you are reading only the CONFIG0 register (this is correct). Therefore, you would only need to follow it with "0x00" to retrieve the 8-bit register value.
[quote user="Abhay Kothari1"]Is the ADS chip on the EVM pre configured ?? [/quote]
After a power-up or reset, the ADS1259 registers will initial to a default value as shown here:
[quote user="Abhay Kothari1"]
To write to registers i am sending 0x40RR 0x00NN 0xDDDD 0xDDDD
To read from registers i am sending 0x20RR 0x00NN followed by 0x0000 to provide clock while ADS transmits data to be rwad
Where RR= Reg Addr , NN = ( numbers of registers to read or write -1) & DDDD = Data to write
[/quote]
I see where you are getting confused. The ADS1259 datasheet defines the WRITE command as "0100 rrrr (40h + 0000 rrrr)". This is only an 8-bit command (0x4R), not a 16-bit command (0x40RR).
Every data transaction is 8-bits; however, READ and WRITE commands require a second op-code byte.
- The first 8-bit opcode defines the READ/Write command and the address to start.
- The second 8-bit op-code defines how many byte to read or write.
- The following bytes are each data reads or writes and should correspond on the number of bytes indicated in the second op-code!
So to read a single register, you would send: 0x20, 0x00*, 0x00**.
To write to a single register, you would send: 0x40, 0x00*, 0xDD**.
* = for multiple register transactions, replace "0x00" with "0x0N"
** = this is where you read out or write data to the ADS1259. Therefore, if N > 0, then you need to send additional bytes.
I hope that helps!
Best Regards,
Chris