DE0-CV User Manual
53
www.terasic.com
May 4, 2015
Table 5-2 Description of 7-segment Display and LED Indicators
Indicator Name
Description
LEDR0
Left button press indicator
LEDR1
Right button press indicator
LEDR2
Middle button press indicator
HEX0
Low byte of X displacement
HEX1
High byte of X displacement
HEX2
Low byte of Y displacement
HEX3
High byte of Y displacement
5
5
.
.
5
5
M
M
i
i
c
c
r
r
o
o
S
S
D
D
C
C
a
a
r
r
d
d
f
f
i
i
l
l
e
e
s
s
y
y
s
s
t
t
e
e
m
m
r
r
e
e
a
a
d
d
Many applications use a large external storage device, such as a SD Card or CF card to store data.
The DE0-CV board provides the hardware and software needed for Micro SD Card access. In this
demonstration we will show how to browse files stored in the root directory of an SD Card and how
to read the file contents of a specific file. The Micro SD Card is required to be formatted as FAT
File System in advance. Long file name is supported in this demonstration.
Figure 5-7
shows the
hardware system block diagram of this demonstration. The system requires a 50MHz clock
provided by the board. The PLL generates a 100MHz clock for the Nios II processor and other
controllers. Four PIO pins are connected to the Micro SD Card socket. SD 4-bit Mode is used to
access the Micro SD Card hardware.The SD 4-bit protocol and FAT File System function are all
implemented by Nios II software. The software is stored in the on-chip memory.
Figure 5-7 Block diagram of the Micro SD demonstration