Altera DE2-115 User Manual download pdf (Page 90)

Figure 6-9 Block Diagram of the SD Card Demonstration

Figure 6-10 shows the software stack of this demonstration. The Nios PIO block provides basic IO

functions to access hardware directly. The functions are provided from Nios II system and the

function prototype is defined in the header file <io.h>. The SD Card block implements SD 4-bit

mode protocol for communication with SD Cards. The FAT File System block implements reading

function for FAT16 and FAT 32 file system. Long filename is supported. By calling the public FAT

functions, users can browse files under the root directory of the SD Card. Furthermore, users can

open a specified file and read the contents of the file.

The main block implements main control of this demonstration. When the program is executed, it

detects whether an SD Card is inserted. If an SD Card is found, it will check whether the SD Card is

formatted as FAT file system. If so, it searches all files in the root directory of the FAT file system

and displays their names in the nios2-terminal. If a text file named “test.txt” is found, it will dump

the file contents. If it successfully recognizes the FAT file system, it will turn on the green LED. On

the other hand, it will turn on the red LED if it fails to parse the FAT file system or if there is no SD

Card found in the SD Card socket of the DE2-115 board. If users press KEY3 of the DE2-115 board,

the program will perform above process again.

1 2 ... 85 86 87 88 89 90 91 92 93 94 95 ... 120 121

No comments

Altera DE2-115 User Manual Page 90