IQ Switch
®
ProxSense
®
Series
Copyright © Azoteq (Pty) Ltd 2022
IQS227-228BEV02 Evaluation Kit User Guide
Page
2
of
10
All Rights Reserved
Revision 1.0
November 2022
Simply plug in the desired module board and turn on the power switch.
Features included in the IQS227-228BEV02:
•
Modular design: Connect one of the supplied plug-in modules into the main board, to
evaluate and compare proximity and touch performance.
•
Reference designs for IQS227B and IQS228B with user proximity and touch detection.
•
Used in Data Streaming Mode: EV-Kit requires Micro-USB cable with Azoteq CT210A.
The EV-Kit main board can also draw power from a USB source by means of the USB Type-C
connector provided on the main board (optional).
2.1 Overview of module boards
Table 1 gives a summary
of the settings burned onto the IC’s. The Green, Blue and Black refer to
the different coloured module boards and the overlay refers to the thickness of the removable
Perspex layers. A 3mm overlay is achievable by stacking three 1mm overlays on top of each
other. The Target value is when the IC performs an Antenna Tuning Implementation (ATI) routine
and adjusts the Compensation (Comp) and Sensitivity (Sense) multipliers for the Counts value to
reach the Target value. The Touch Threshold (TTH) sets the point where a Touch event is
triggered. This is calculated as a fraction of the current LTA value. For simplicity, an example of
this calculation will be given.
Example:
With a TTH set to 48 and a Long Term Average (LTA) of 512, the equivalent
ΔCounts value is
calculated as follow:
∆𝐶𝑜𝑢𝑛𝑡𝑠 = 𝐿𝑇𝐴 ×
𝑇𝑇𝐻
256
= 512 ×
48
256
= 96
This means that when the Counts value is
ΔCounts below the LTA, the Touch event will be
triggered.
Table 1: Settings for the module boards
IC
Module
Board
Overlay
Target
TTH
Multiplier
Compensation
Multiplier
Sensitivity
IQS227B
Green
1mm
512
48
13
2
Blue
2mm
1024
48
14
2
Black
3mm
1024
24
Full ATI
IQS228B
Green
1mm
1024
72
13
2
Blue
2mm
1200
72
7
2
Black
3mm
1200
24
Full ATI
3 Standalone Operation
3.1 Powering on the device
In order to power the device, make sure the main board is set up as follow:
•
Connect the IQS227B (green board) plug-in module board.
•
Put 1 overlay on the base board.
•
Move the slide switch to the ON position.
Always switch OFF the device before making alterations to the main board. This is needed for the
Integrated Circuit (IC) to adjust to the main board setup.
There are 3 alterations available:
•
The plug-in module board can be exchanged for another board in the EV-Kit.
•
The overlays can be added or removed as needed.
•
The jumper can be shifted to connect the adjacent pads to the button.
