NXP Semiconductors AN12868, Быстрый старт

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1 Introduction
This application note introduces a parallel interface for the camera solution for
LPC55(S)xx. It includes the introduction of camera interface, features and API
routines, and demo.
2 Target application
The camera interface can be used as important part of camera usage as below:
• Object detection
• Gesture recognition
• Color recognition
• QR code scanning, and so on
3 Introduction of camera interfaces
A typical camera interface supports at least one parallel interface, although
nowadays many camera interfaces begin to support the MIPI CSI interface.
The camera parallel interface consists of the following lines:
• Data line (D[0:11]):
These parallel data lines carry pixel data. The data transmitted on these
lines change with every Pixel Clock (PCLK).
• Horizontal Sync (HSYNC)
This is a special signal that goes from the camera sensor. An HSYNC indicates that one line of the frame is transmitted.
• Vertical Sync (VSYNC)
This signal is transmitted after the entire frame is transferred. This signal is often a way to indicate that one entire frame
is transmitted.
• Pixel Clock (PCLK)
This pixel clock changes on every pixel.
The application note only focuses on Digital-Video-Port (DVP) interface which is parallel interface.
4 Features of camera interface
• Supported formats (8-bit): RGB565
• Maximum image transfer rate: 30 fps for QVGA(320 × 240). For small RAM parts, reduce the size of image and frame
rate.
• Camera module tested: OV7673
Contents
1 Introduction......................................1
2 Target application............................1
3 Introduction of camera interfaces....1
4 Features of camera interface.......... 1
5 Function description........................ 2
5.1 Camera interface engine............. 2
5.2 Camera driver library................... 2
5.3 LCD display..................................2
5.4 System clock................................2
5.5 Clock source of camera............... 2
5.6 I
2
C interface................................. 2
5.7 Memory usage............................. 2
5.8 Other supported camera modules
.....................................................2
6 Pin description.................................3
6.1 Connection of interface................3
6.2 Requirement of interface............. 4
7 Library and API routine................... 4
7.1 Library..........................................4
7.2 API routine................................... 4
7.3 API routine description.................4
7.4 Code detail description................ 4
8 Demonstration.................................7
9 Revision history...............................8
A Purchasing LCD module and camera
module used in this demo............... 8
AN12868
Camera Interface in LPC55(S)xx
Rev. 3 — 07 September 2021
Application Note