TM4C123G LaunchPad - 7 Segment LED Interface
Revision as of 06:23, 22 January 2018 by Jshankar (Created page with "== Seven-segment LED interfacing == The 7-seg LED can have '''common anode''' or '''common cathode'''. With common anode, the anode of the LED is driven by the positive supply...")
Seven-segment LED interfacing
The 7-seg LED can have common anode or common cathode. With common anode, the anode of the LED is driven by the positive supply voltage and the microcontroller drives the individual cathodes LOW for current to flow through LEDs to light up. In this configuration, the sink current capability of the microcontroller is critical. With common cathode, the cathode of the LED is grounded and microcontroller drives the individual anodes HIGH to light up the LED. In this configuration, the microcontroller pins must provide sufficient source current for each LED segment. In either configurations, if the microcontroller does not have sufficient drive or sink current capacity, we must add a buffer between the 7-seg LED and the microcontroller. The buffer for the 7-seg LED can be an IC chip or transistors.