AFE4400SPO2EVM: Documentation for SPI communication

GreenAndGrey

Part Number: AFE4400SPO2EVM
Other Parts Discussed in Thread: AFE4400,

I'd like to set up an application that communicates with the evaluation module but I can't find the relevant documentation. I did find the SPI communication information for the AFE4400 but not the evaluation module itself - could someone point me in the right direction?

over 8 years ago

0 Praveen Aroul over 8 years ago

TI__Mastermind 49956 points

Hello,

The Message Communication Protocol document details the communication format for the AFE4400SPO2EVM.

You will be able to find the document under C:\AFE4400EVMFWSRC-v1.4\AFE4400EVM_FW_SRC_v1.4_Release

0 GreenAndGrey over 8 years ago in reply to Praveen Aroul

Expert 1060 points

Hi Praveen,

That document doesn't specify the SPI communication details - can you please elaborate on the data rate, etc?

0 Prabin Yadav over 8 years ago in reply to GreenAndGrey

TI__Genius 12575 points

Hi,

Here are some details,
SPI clock is 16MHz,
Idle state of SCLK is LOW,
Data is sampled on the rising edge and it is changed on the falling edge.

BTW, if you are still using the on board MSP430 controller to communicate with the AFE4400, you don't need to worry about the SPI interface. The MSP430 is programmed to handle SPI interface, you just have to give the respective commands through the UART following the protocol mentioned in document that Praveen had suggested. Your custom application should be able to give these commands to MSP430 through the UART.

Regards,
Prabin

0 GreenAndGrey over 8 years ago in reply to Prabin Yadav

Expert 1060 points

Thank you both for the information!

0 GreenAndGrey over 8 years ago in reply to GreenAndGrey

Expert 1060 points

As a follow-up to this, is there a recommended baud rate while working with the EVM? I want to collect the voltage values as read from the serial port and display an interactive plot like the GUI does. I find that setting the serial port timeout to a very low number doesn't give me all the data samples requested so it seems that the serial data is not arriving in a continuous manner.

0 GreenAndGrey over 8 years ago in reply to GreenAndGrey

Expert 1060 points

I'm using a baud rate of 230400. When I read the data on the serial line, it looks like I'm receiving about 2200 bytes in 1 second, and that translates to 100 samples. The data sampling rate is 500 sps, so obviously my data collection rate is also not optimal.

0 Prabin Yadav over 7 years ago in reply to GreenAndGrey

TI__Genius 12575 points

Hi,

Even in the continuous mode, the EVM will give out the data at the rate defined by sampling frequency (i.e. PRF). So your timeout will depend on your sampling frequency.
The EVM will transmit the data at the baud rate of 230400, the separation between such transfer will be defined by PRF.

Regards,
Prabin

0 GreenAndGrey over 7 years ago in reply to Prabin Yadav

Expert 1060 points

230400 seems to work best, thank you.

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AFE4400SPO2EVM: Documentation for SPI communication