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This original tutorial is created by Core Electronic Technology (Shanghai) Co., Ltd. (ALINX), copyright belongs to the company, if you need to reprint, you need to authorize and indicate.
Suitable for board models:
AXU2CGA / AXU2CGB / AXU3EG / AXU4EV-E / AXU4EV-P / AXU5EV-E / AXU5EV-P / AXU9EG / AXU15EG
The Vivado project is "ps_hello / vivado"
The VITIS project is "PS_SD / VIS"
This chapter describes the BMP image of the SD card using the FATFS file system module and displayed by DP.
Fatfs Introduction
FATFS is a universal file system module for implementing a FAT file system in a small embedded system. FATFS's writing follows ANSI C, so it does not rely on the hardware platform. It can be embedded in a cheap microcontroller, such as 8051, PIC, AVR, SH, Z80, H8, ARM, etc., do not need to make any modifications.
The application calls the FATFS system module through the API function, thereby controlling these storage devices in the SD card.
The FATFS system provides a lot of API functions, and we list the API functions that will be used in our routine below.
F_mount - Register / log out of a work area (Work Area)
f_open - Open / create a file
f_close - Close a file
f_read - read file
f_write - write files
About the introduction and instructions of the API function, you can refer to the following website for more step-by-step understanding, this website
The instructions and examples of each API function are given.
http://elm-chan.org/fsw/ff/00index_e.html
2. VITIS program development
1) Open the VITIS software, we have generated a SD_BMP project for everyone. Here you need to configure the properties of the BSP support package, select the XILFFS item in Board Support Package Set, enable project to support the Xilffs file system.
About XILFFS libraries is the FAT file system support package provided by Xilinx, and users can call the API function to be implemented.
Operation of equipment such as SD / EMMC. Xilffs reservoir mainly contains File System Files and Drive Layer Files.
2) About the introduction and application of XILFFS libraries, you can refer to the following xilinx official website link:
http://www.wiki.xilinx.com/xilffs
3) Next, let's see the project code of SD_BMP. In the engineering code, we need to read the image data of the BMP format stored in the SD card. After removing the image header, put the display buffer in the DP, then implement the image in the DP display.
4) In the bmp.c file, we add a BMP_READ function, first open the picture file of the BMP in an SD card with a f_open function in this function. Then read the front 54 bytes of this file, because 54 bytes of the BMP image file are image header files, containing the pixel size information of the image. The read image data in one line is stored in the DP Frame display buffer.
Since BMP storage is upside down, the order is adjusted in the bmp_read function, and stored in the FRAME buffer.
5) At the same time we also prepare the BMP file head structure, and some commonly used image head settings, placed in the bmp.h file.
6) In conjunction with the display of the kitten picture, save the kitten picture into the BMP format, save it to the SD card, in the BMP_WRITE function, combine BMP header and BMP data to save to the SD card.
7) In the main function, call the bmp_read function to implement a pair image from the SD card to the DP display buffer storage, the file name of the BMP image here is the same as the file name stored in the SD card. Write the kitten picture to the SD card with BMP_WRITE.
3. Verification on board
1) First, you need to first store 1920 * 1080 pixels, 24bit's BMP file to SD card, file name is 1.BMP (files in engineering directory), in case the SD card into the card .
2) Development Board Connect the DP display, then powered up, after downloading the program runs, we can display the image of the 1.BMP file stored in the SD card on the DP display.
3) After the development board can be discharged, insert the SD card to the computer, you can see more Cat.BMP, read the full text
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