Pmod MicroSD Reference Manual
The Digilent Pmod MicroSD (Revision A) allows system boards to read from and write to
microSD cards. With no limitation on the file system or memory size of the microSD card, users
will be able to store and access large amounts of data from their system board.
Features
MicroSD card slot
Store and access large amounts of data from your system board
No limitation on file system or memory size of microSD card used
1‐bit and 4‐bit communication
12‐pin Pmod port with SPI interface
Functional Description
The Pmod MicroSD is a great way to store and access information on a device that can then be
accessed by outside devices such as a phone or computer.
Interfacing with the Pmod
The Pmod MicroSD is designed to communicate with the host board primarily through the SPI
protocol. By default, the microSD card itself is defined to boot up in SD mode, but will enter
into SPI mode when the Chip Select line is pulled low. The actual technique of writing to and
reading from specific locations on an microSD goes beyond the scope of this document, but the
complexity of the process is nicely abstracted away within the chipKIT SD library and
Digilent PmodSD IP Core.
A pinout description table for the 2×6 pin header on the Pmod MicroSD can be found below:
Connector J1‐ Pin Descriptions
Pin
Signal
Description
Pin
Signal
Description
1
~CS
Chip Select / Data3
7
DAT1
Data 1
2
MOSI
MOSI / Command
8
DAT2
Data 2
3
MISO
MISO / Data0
9
CD
Card Detect
4
SCK
Serial Clock
10
NC
Not Connected
5
GND
Power Supply Ground
11
GND
Power Supply Ground
6
VCC
Power Supply (3.3V)
12
VCC
Power Supply (3.3V)
Any external power applied to the Pmod MicroSD must be within the specifications of the
inserted microSD card. As determined by the SD card association, this voltage range must be
within 2.7 to 3.6 volts. The 3.3 operating voltage on Digilent system boards nicely complies with
this standard.
Physical Dimensions
The pins on the pin header are spaced 100 mil apart. The PCB is 1.8 inches long on the sides
parallel to the pins on the pin header and 1.8 inches long on the sides perpendicular to the pin
header.
https://reference.digilentinc.com/reference/pmod/pmodmicrosd/reference‐manual 6‐19‐18
