STMicroelectronics AN594 Direct LCD Drive with ST62 MCUs Application Note

About this manual

The document details a cost-effective method to drive Liquid Crystal Displays (LCD) using standard ST62 microcontroller units, eliminating the need for dedicated LCD driver chips. It explains the electrical requirements for LCD operation, including RMS voltage and multiplexing rates.

Two specific implementation solutions are presented: one based on the ST6215 MCU operating without software interrupts, and another utilizing the ST6265 with timer-based interrupt control. Both approaches minimize program size and CPU usage while reducing external component count.

What's inside

• Introduction
• LCD requirements
• Direct LCD drive
• Duplexed LCD drive
• Example of duplexed LCD drive with ST6215x
• Example of duplexed LCD drive with ST6265x

Frequently asked questions

What microcontrollers are used in the examples?

The document presents solutions based on standard ST621xx and ST626xx MCUs, specifically using an ST6215 without interrupts and an ST6265 with timer interrupts.

How many resistors are needed for the duplexed drive?

By using an MCU with flexible I/O pin configuration such as the ST6215x or ST6265x, duplexed LCD drive can be made with only 4 additional resistors.