I2C Bus Interface to SX1509 Keypad Engine
SX150_keypad_I2C_interface.py
This sample is a Python module from a project that uses a numeric keypad as a means for a user to enter a security access code into a device. The security code that is entered is compared against codes stored in a database and if there is a match then the device is signaled to unlock itself. The module also provides control of two LEDS that are mounted near the keyboard and that provide the user with accept/reject feedback regarding the keyed-in code. The keypad and LEDS are connected to a Semtech SX1508 keypad engine/GPIO extender that is configured and controlled via an I2C bus.
The SX150_keypad_I2C_interface.py module contains three object classes: I2C_KeyPad – configures and controls with the keypad engine I2C_LED – configures and controls the LEDs UserInterfaceThread - provides the application with a high level interface via an ‘unlock event’
Associated files:
- sx1509.pdf– SX150 Device communications spec.