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Hello,

I am trying to interface with the TI ADS1298 using the EB013 and am having some trouble. I am starting with the basics by attempting to read the ID Control register (as defined on page 42 of the datasheet http://focus.ti.com/lit/ds/symlink/ads1298.pdf). I am not getting anything back from the device. Here is what I am doing in my flowchart:

1) SPI_Init
2) Create Variable "bytetosend" and assign it to be 32 (0010 0000 binary - read register 0) First opcde - Page 40 of the datasheet
2) delay 10ms
3) SPI_SEND_CHAR bytetosend
4) delay 10ms
5) bytetosend=0 (0000 0000 binary - to read 1 register location) Second opcode - page 40 of the datasheet
6) SPI_SEND_CHAR bytetosend
7) Create variable "bytereceived"
SP_Get_Char bytereceived
9) delay 10ms
10) LCD_DISPLAY Start
11) delay 10ms
12) LCD_DISPLAY_PrintNumber bytereceived (expected output should be 2, but we don't get anything)

I have tried removing the delays and making them longer and still don't get anything back.

What am I doing wrong? Am I not doing something correctly with the SPI component?

Thank you!
Marty

Hello Marty

where do you manage the CS (chip select) ?

Daniel

At the moment /CS is tied low.

Marty

Hello Marty,

This may be bad news to you but a lot of SPI devices actually need the CS line to begin high and then be pulled low to activate a kind of wake up interrupt. The flip side is that some SPI devices need the CS line to go back high to then process the received command. Therefore I would dig out the old soldering iron and attach the CS line to an I/O pin.

Thanks for the reply.

I will reattach it to an i/o pin and try again. I will let you know if that makes a difference.


Marty

Hello,

I am still stuck on this. I have the following connections between the ADS1298 and the PIC:

ADS1298 SCLK -> 18F4550 Pin 34 (SCLK)
ADS1298 SDI -> 18F4550 Pin 26 (SDO)
ADS1298 SDO -> 18F4550 Pin 33 (SDI)
ADS1298 /CS -> 18F4550 Pin 8 (RE0)
ADS1298 SPI Start -> 18F4550 Pin 9 (RE1)
ADS1298 Reset -> Pin 10 (RE2)
ADS1298 SPI DRDY -> Pin 35 (Int2)

I have attached the flowchart that I am using. Anyone got any suggestions on what I am doing wrong?

Thank you very much!!
Marty

I am still stuck on making this work. I believe that things are working to read data via SPI, but I don't think it is sending characters. Is it possible I should use something other than the SPI_Legacy? What about SPI_SEND_CHAR - would that be correct? I have tried sending characters and bytes and nothing seems to work.

Any suggestions?

Hello Marty

Try the attached file, I've modified the "ADS1298Init" macro.
I'm not sure of my work, ADS1298 is a big component with lot of configuration.

Can you take a look on the SPI signals with an oscilloscope or a logic analyser ?

Good luck

Daniel

Hi,

5) bytetosend=0 (0000 0000 binary - to read 1 register location) Second opcode - page 40 of the datasheet

OPCODE 2 seems to be 01h (0000 0001b) and not 00h.

Regards,

Nicolas Lopez F.