Master and slave type keyboard controller based on MCU (microprogrammed control unit) and CPLD (complex programmable logic device)

Abstract

The invention provides a keyboard controller which comprises a master module based on an MCU (microprogrammed control unit) and a slave module designed based on a CPLD (complex programmable logic device); a master communicates with a slave through a bus; the slave detects every key of an independent keyboard by adopting CPLD device design, implements shake elimination processing and also outputs an LED (light emitting diode) control state; each IO (input / output) interface of the slave can be designed to be a key detection port or an LED state output port; a reserved IO interface can be used for freely and selectively increasing or decreasing a key or an LED; the master communicates with the slave through the bus to acquire key information of the independent keyboard and controls the slave to output the state; furthermore, the master encodes the keys to realize a function of a protocol layer and sends codes to a computer through an USB (universal serial bus) interface and a PS2 (play station 2) interface. Keyboard designs with different distributions and different functions can be realized by increasing or decreasing the number of the slaves; the master can change the function and the code of each IO of each slave by modifying firmware of the master.

Description

technical field [0001] The invention relates to a novel keyboard controller, in particular to a master-slave keyboard controller which is designed based on MCU and CPLD and can be freely developed, expanded and split. Background technique [0002] In the operation of operating equipment, the keyboard is a commonly used device to realize human-computer interaction. The keyboard is composed of keys, backlight and main controller. Due to the limitation of the IO resources of the controller, the existing keyboards are all designed with determinant matrix keyboards. Multiple buttons share limited IO resources, and the mode of software scanning and query is used to judge whether the buttons are pressed or released. [0003] Existing keyboards are all a master control. In the keyboards used by computer equipment, MCU is generally used as the master control. Some keyboards in test and measurement equipment such as oscilloscopes and signal sources use CPLD devices as controllers. A...

AI Technical Summary

Problems solved by technology

A single MCU or CPLD as the main control consumes a lot of resources in the process of matrix keyboard scanning and button debounce. The controller must complete the encoding and decoding functions after completing the button detection, and transmit it to the operating device through the USB HID protocol and PS2 protocol.

When realizing complex keyboard control and gorgeous backlight control, there is a key delay, etc.

[0004] The existing controller has a single function, and it is impossible to realize free and flexible expansion, splitting the keyboard and changing the functions of the keyboard controller

[0005] To sum up, the existing keyboard controllers are not flexible enough and have a single function, especially when the user needs to change or add some specific functions.

The matrix keyboard design consumes a lot of MCU resources, which limits the complex and diverse design requirements of users

The main control is not modularized, the circuit scheme cannot be changed flexibly, and new functions cannot be added flexibly

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