M I K R O E L E K T R O N I K A S O F T W A R E A N D H A R D W A R E S O L U T I O N S F O R T H E E M B E D D E D W O R L D
EasyAVR
USB
4
EasyAVR4 User
’
s Manual
MikroElektronika
Development
tools
3
32
2
page
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To enable MMC card you must turn on switches 1, 2, 3 and 4 on SW3. By doing that, micro-
controller’s SPI comunnication lines (SDI, SDO and SCK) and Chip Select are connected to
MMC. Working voltage of EasyAVR4 is 5V DC, while working voltage of MMC card is
3.3V DC. Because of that, there is a voltage regulator on-board with MMC card
(MC33269DT-3.3). Data lines from microcontroller to MMC card must be also adjusted to
3.3V. It is done with resister voltage dividers as shown on Figure 42.
MMC card is used as storage media for a portable devices, in a form that can easily be
removed for access by a PC. For example, a digital camera would use an MMC card for
storing image files. With an MMC reader (typically small box that connects via USB or
some other serial connection) you can easily transfer data from MMC card to your comput-
er. Microcontroller on EasyAVR4 communicates with Multi Media Card via SPI communi-
cation.
MMC/SD (MULTIMEDIA CARD)
Figure 41.
MMC slot on-board
Modern computers, both lap-
tops and desktops, often
have SD slots, which can
read MMC cards.
MMC/SD
MASS STORAGE
MMC/SD
MASS STORAGE
SUPPORTED
SUPPORTED
256MB
