For AFE4404EVM initialize sequence

Moonsik Choi

Prodigy 50 points

Other Parts Discussed in Thread: AFE4404, AFE4404EVM

Hello everyone.

I was test afe4404 in TI-RTOS.

I can find some problem. I was setting to afe4404 register 0h ~3Ah.

I refer to default register setting at AFE4404 EVM GUI.

Then i can look all LED(green, red, ir) off. They wasn't on state.

So i want to know correct initialize sequence for AFE4404.

Could you help me?

over 9 years ago

0 Moonsik Choi over 9 years ago

Prodigy 50 points

in 4th line, default register means making all LED on state.

0 Praveen Aroul over 9 years ago in reply to Moonsik Choi

TI__Mastermind 49946 points

Hello,

Prior to reading out any other register, the REG_READ bit (Register 0, bit 0) needs to be additionally set to '1'.
Additionally Register 0 is a write only register. Any attempt to read this register after setting REG_READ bit will clear the bit.
Also ensure the RESETZ signal is pulled high.

Do you know the status of the AFE clock?
Are you using external clock mode (default after reset) or internal oscillator mode?

Here is a possible initialization sequence.
After ensuring stable supplies to TX_SUP, RX_SUP and IO_SUP pins,
1. trigger hardware reset by applying a 25-50us active low pulse on RESETZ pin.
2. if using external clock mode, provide the clock on CLK pin.
2. initialize the AFE registers
3. for verification, enable the REG_READ bit and read back the registers from address 1.

0 Likhitha Neelisetty over 9 years ago in reply to Praveen Aroul

Prodigy 100 points

Hi,

Please provide firmware source code of AFE4404EVM board.

Thank you

0 Praveen Aroul over 9 years ago in reply to Likhitha Neelisetty

TI__Mastermind 49946 points

Hello Likhitha,

We will post the AFE4404 firmware source code on TI.com soon.

0 Moonsik Choi over 9 years ago in reply to Praveen Aroul

Prodigy 50 points

Hello Praveen,

I want to use SpO2 monitoring mode in AFE4404.

But i can't find register setting about SpO2 mode in afe4404datasheet.

Could you help me?

0 Praveen Aroul over 9 years ago in reply to Moonsik Choi

TI__Mastermind 49946 points

Hello Moonsik,

There is no specific register setting to enable SpO2 mode in the device.
Based on the LED configuration (Red and IR LED), you should be able to
1. extract the PPG signals corresponding to the two wavelengths
2. compute the ratio of ratios and
3. estimate the peripheral oxygen saturation based on the empirical calibration curve.

0 Moonsik Choi over 9 years ago in reply to Praveen Aroul

Prodigy 50 points

Hello Praveen,

I want to check AFE4404 current consumption everything case.

For example, on green LED and on PD case.

But i can't find imformation about current consumption in AFE4404 datasheet.

Could you help me?

Thank you!

0 Praveen Aroul over 9 years ago in reply to Moonsik Choi

TI__Mastermind 49946 points

Hello Moonsik,

The Electrical Characteristics table in the AFE4404 datasheet lists the current consumption of the device based on the different supplies under different operating or test conditions.
The LED currents need to be calculated separately based on the LED current register setting.

Figure 14 illustrates the LED current value versus the LED current setting code. The mode marked as 50-mA LED Current Mode corresponds to the default setting of ILED_2X = 0, whereas the mode marked as 100-mA LED Current Mode corresponds to ILED_2X = 1. The ideal slope of these curves corresponds to 0.793 mA per code for the 50-mA current mode and 1.587 mA per code for the 100-mA current mode. However, a small deviation from these ideal values can exist from device to device, and can be viewed as a gain error in the LED current versus code. This deviation can be larger for the 100-mA current mode, with slight saturation of current
especially at the high-current settings.