I followed application example on page 42 of fdc2212 manual (http://www.ti.com/lit/gpn/fdc2212).
I am interfacing FDC2212 from stm32f303 uC, FDC2212 respond correctly to i2c communication (returns correct MANUFACTURER_ID), but when reading status I get 0 and also all values DATA_CH0 and DATA_LSB_CH0 are always 0.
What I am doing wrong?
Code is available at:
On osciloscope I clearly see signal on 18uH inductor. Picture of scope attached.
After changing device ative bit, I Start reading values:
So this line:
//0b0 0 1 0 1 0 0 0 0 00 0001 device is active - no sleep
Fixed reading...
Whole setup of FDC2212_CONFIG_REGADDR 0x1A register:
//reset device
write16FDC(FDC2212_RESET_DEV, 0b1000000000000000); //reset device
//0b00 00 0001 RESERVED
//0b0 0 00 0001 Normal current drive (auto scan is enabled)
//0b0 0 0 00 0001 Disable interrupt pin
//0b0 0 0 0 00 0001 RESERVED
//0b0 0 0 0 0 00 0001 Use internal oscilator
//0b1 1 0 0 0 0 00 0001 RESERVED
//0b0 0 1 0 0 0 0 00 0001 full current mode
//0b1 1 0 1 0 0 0 0 00 0001 RESERVED
//0b0 0 1 0 1 0 0 0 0 00 0001 device is active - no sleep
//0b00 00 0 1 0 1 0 0 0 0 00 0001 Contineous reads on CH0
//FDC2212_CONFIG_REGADDR 0x1A
write16FDC(FDC2212_CONFIG_REGADDR, 0b0001010000000001); //set config
Now I would like to extend the range of FDC2212 - it seems I can detect movements only within 3 centimeters.
Can I adapt pcb somehow (coil or cap modification?) Or it is possible to do it via software?
Here is schematic of what I use:
Sense area is rectangular 1cm wide and 9cm in length.
This sense area is GND shielded on another side of pcb with raster ground plane.
Hi Luke,
I did first two points you suggested but that has not improved sensitivity and I am already using maximal r_count in my code when initializing chip:
//rcount maximized for highest accuracy
write16FDC(FDC2212_RCOUNT_CH0_REGADDR, 0xFFFF);
You can see video where I show sensitivity is still very small...
According to TI webench site 30cm distance sense should be possible with fdc2212 - or I am missing something? See screenshot from webench:
I actually haven't predicted to use external oscillator on my hardware.
This are readings that I have from sensor.
Since values are kind of drifting - I need to find good sample code to detect hand touch. So actually somthing to adapt to value of capsense when hand is not present near sensor.
In bottom picture you see hand got near the sensor 5 times. So how would I go to define what vaule should be trigger value for detecting hand touch? Any idea?
