AFE4300 evm - multiboard and multiplexer

Soochan,

We have received your post and hope to have a response back to you soon.

Soochan,

1. Do you need a fast sampling rate? More than 860 SPS?

2. I'm confused what you are asking here. Can you explain what you want the GUI to do? I will be able to tell you whether this is possible or not using the GUI.

Hello, Amy,

1. I don't want a fast sampling rate more than 860, because it would be impossible.

For one channels, I got data well using Python script.

What I want to get the multi-channels data with at least 50Hz sampling rate per each channel.

I have tried it, but failed.

2. To solve the upper problem, I connected two boards and tried, but AFE4300 GUI program recognized only one board.

Did you understand ?

Soochan

Hello Soochan,

1. Could you elaborate on the scheme you are following to get the multi-channel data?

I am assuming that you are setting the 50 Hz sampling rate in the python script because the AFE4300 does not support 50 sps.

Execution of Python scripts has its own latency which is dependent on the system CPU resources.

Did you check if you are able to get the multi-channel data at lower sampling rate say 10 Hz?

What is the data rate that you have set in the AFE?

2. The GUI does not support multiple evaluation boards connected to the PC.

Hello, Praveen,

Can I set the sampling rate in the AFE ?
I didn't and just got the data using API function supported by Python.
Without delay, the data were not accurate . If I give delay, the data rate is too late.
That is my problem.

Can I control directly the AFE4300 evm by LabVIEW using dll ?
I tried to call API function using LabVIEW but it also was failed.

I want to get the FWR or IQ mode data while current source channel(IOUT?) are fixed and voltage detection channel(VSEN?) are changed.

2. The GUI does not support multiple evaluation boards connected to the PC.
Thank you. I will not try anymore to run multiple program.

Soochan Kim

Soochan,

Yes you can set the output data rate in the AFE through the GUI. Refer to the AFE4300 datasheet for more details.

The FW rectifier or IQ demodulator output is bandwidth limited set by the internal resistor (5KOhm) and external capacitor 4.7uF. The time constant (tau) is about 25ms. You may want to wait for atleast 10 tau (250ms) for the channel data to settle. That is the reason why your data is not accurate without delay.

Could you explain your application that warrants switching sensing channels at such fast data rates?

250ms is too slow. Can I make more faster if I change the external resistor ?

I apply it to impednace-plethysmography which is measure blood flow not body fat. So I need more fast data rate.

Thank you.

Now I get data using Python scripts on AFE4300-GUI.

I like to get the data directly from AFE4300 EVM board without running AFE4300-GUI program.

Could you suggest new method for me?

I have attached the message communication protocol for the AFE4300 EVM.

/cfs-file/__key/communityserver-discussions-components-files/73/3107.Message-Communication-Protocol-_2D00_-AFE4300EVM_2D00_PDK.pdf

Thanks for your reply.

I send some commands through hyperternal, but there is no response.

What is baud rate ?

I tested 9600, 8, none, off (speed, datasize, parity, handshake).

Below are the serial port settings:

57600, 8, none, off

Good,
I got the 0xA, 0xD after radc? command.
But AFE4300 doesn't start sending ADC data packets continuously. :-(

Hello, Praveen Aroul,

I can see the AFE4300 response like 0x0A, 0x0D when I send command.
But there is no action.

for example, when I send "rst?", the board return 0x0A, 0x0D but the board doesn't reset.
when I send "r126789", it returns 0x0000.

when I send "sadc?", it returns just 0x0A, 0x0D. There is not additional data.

Help me.

Thank you.

Soochan,

The rst? command issues an hardware reset to the device. When a rst? command is issued, you will see an active low pulse on the RESET pin. Refer to the datasheet for register values after reset.
For example: after reset, reg 01h will be 01C3h

After reset, you will need to configure the AFE for appropriate measurement: voltage monitor, AUX1/2, weigh scale or BCM. You could use the AFE4300 GUI for the register configuration.