README.md
1| Supported Targets | ESP32-S2 |
2| ----------------- | -------- |
3
4# Matrix Keyboard Example (based on Dedicated GPIO)
5
6(See the README.md file in the upper level 'examples' directory for more information about examples.)
7
8## Overview
9
10This example mainly illustrates how to drive a common matrix keyboard using the dedicated GPIO APIs, including:
11
12* Manipulate the level on a group of GPIOs
13* Trigger edge interrupt
14* Read level on a group of GPIOs
15
16Dedicated GPIO is designed to speed up CPU operations on one or a group of GPIOs by writing assembly codes with Espressif customized instructions (please refer TRM to get more information about these instructions).
17
18This matrix keyboard driver is interrupt-driven, supports a configurable debounce time. GPIOs used by row and column lines are also configurable during driver installation stage.
19
20## How to use example
21
22### Hardware Required
23
24This example can run on any target that has the dedicated feature (e.g. ESP32-S2). It's not necessary for your matrix board to have pull-up resisters on row/column lines. The driver has enabled internal pull-up resister by default. A typical matrix board should look as follows:
25
26```
27row_0 +--------+-------------------+------------------------------+-----------------+
28 | | |
29 | + | + | +
30 | +-+-+ | +-+-+ ...... | +-+-+
31 . +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
32 . | | |
33 . . | . | . |
34 . | . | ...... . |
35 . | . | . |
36 . | . | . |
37 | | |
38row_n +--------+-------------------+------------------------------+-----------------+
39 | | | | | |
40 | + | | + | | + |
41 | +-+-+ | | +-+-+ | ...... | +-+-+ |
42 +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
43 | | |
44 | | |
45 | | |
46 + + +
47 col_0 col_1 ...... col_m
48```
49
50### Build and Flash
51
52Build the project and flash it to the board, then run monitor tool to view serial output:
53
54```
55idf.py -p PORT flash monitor
56```
57
58(Replace PORT with the name of the serial port to use.)
59
60(To exit the serial monitor, type ``Ctrl-]``.)
61
62See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
63
64## Example Output
65
66```
67I (2883) example: press event, key code = 0002
68I (3003) example: release event, key code = 0002
69I (5053) example: press event, key code = 0001
70I (5203) example: release event, key code = 0001
71I (6413) example: press event, key code = 0000
72I (6583) example: release event, key code = 0000
73I (7963) example: press event, key code = 0003
74I (8113) example: release event, key code = 0003
75I (8773) example: press event, key code = 0103
76I (8923) example: release event, key code = 0103
77I (9543) example: press event, key code = 0203
78I (9683) example: release event, key code = 0203
79```
80
