Firmware
TCA8424
24-bit 1.65- to 3.6-V 1MHz I2C/SMBus keypad scanner with interrupt & 128 key support
Data sheet
TCA8424
- Operating Power-Supply Voltage Range of 1.65V to 3.6V
- Supports FM+ I2C Operation up to 1MHz
- Can Support up to 128 (8x16) Key Scan
- Internal Power-On-Reset
- Open Drain Open Drain Active Low INT Output
- Noise Filter on SCL/SDA and Inputs
- Open Drain Outputs Can Sink up to 12mA Current for LED
- Hardware Coded HID and REPORT Descriptors
- Available With Preprogrammed Keyboard Map
- Software Reset per HID Over I2C Standard
- Internal Pull-up Resistors Make Implementation Easy
With no Need for External Components - HID Over I2C Commands Supported
- RESET
- GET REPORT
- SET REPORT
- SET POWER
- Fixed Length 8-byte INPUT Report can Detect up to 6
Simultaneous Key Presses Excluding Modifiers (CTRL, ALT,
SHIFT) - INPUT Report Generated on Key Press and Release
- Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
- ESD Protection Exceeds JESD 22
- 1000-V Human-Body Model (A114-A)
This 128 key scan device is specifically targeted towards end equipment that runs on Windows 8 operating system. The device is fully compliant with the HID over I2C specification defined (ver 1.0) defined by Microsoft. The HID and report descriptors are hard coded into the device so that they don’t need to be programmed at production. The device also comes with a preprogrammed keyboard map that is compatible with most standard laptop/notebook keyboards. However, the device also available without a pre-programmed keyboard, so that any keyboard map may be written into it at production.
The device generates INPUT reports of standard 8-byte length with the 1st byte being the modifier byte. After the keyboard map is programmed into the device it automatically recognizes the row/column location of the modifier keys based on their usage code. It is capable of detecting and reporting up to six simultaneous key presses plus eight modifiers. It generates an input report on each key press and each key release.
The device also supports LED indicators that are standard on a keyboard. Different variations support 2,4 or 8 LED outputs. Each output has open drain architecture and is capable of sinking up to 12mA of current. The LEDs are controlled by a standard OUTPUT report as described in the HID over I2C standard.
Technical documentation
No results found. Please clear your search and try again.
View all 7 | Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | Low-Voltage 8x16 Keyboard Scanner With HID over I2C Compliant Interface datasheet | 27 Mar 2013 | |
| Selection guide | I2C Infographic Flyer | 03 Dec 2015 | ||
| Application note | Understanding the I2C Bus | PDF | HTML | 30 Jun 2015 | |
| Application note | Maximum Clock Frequency of I2C Bus Using Repeaters | 15 May 2015 | ||
| Application note | I2C Bus Pull-Up Resistor Calculation | PDF | HTML | 13 Feb 2015 | |
| Application note | OTP Creation Guide | 27 Mar 2013 | ||
| EVM User's guide | TCA8424 Evaluation Module User's Guide | 22 Feb 2013 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.
Evaluation board
TCA8424EVM-038 — TCA8424EVM-038
The TCA8424 EVM showcases the capabilities and benefits of using the TCA8424 in a keyboard scanner application. This EVM is designed to allow the user to program their own OTPs and then test the OTP in a system use case.
User guide: PDF
GUI for evaluation module (EVM)
SCDC004 — TCA8424 GUI
Supported products & hardware
Products
I2C general-purpose I/Os (GPIOs)
Hardware development
Evaluation board
Simulation tool
PSPICE-FOR-TI — PSpice® for TI design and simulation tool
PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Simulation tool
TINA-TI — SPICE-based analog simulation program
TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
| Package | Pins | Download |
|---|---|---|
| VQFN (RHA) | 40 | View options |
Ordering & quality
Information included:
- RoHS
- REACH
- Device marking
- Lead finish/Ball material
- MSL rating/Peak reflow
- MTBF/FIT estimates
- Material content
- Qualification summary
- Ongoing reliability monitoring
Information included:
- Fab location
- Assembly location
Support & training
TI E2E™ forums with technical support from TI engineers
Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.
If you have questions about quality, packaging or ordering TI products, see TI support.