14
BIGdsPIC6 Development System
MikroElektronika
page
9.0. MMC/SD Connector
The MMC/SD connector enables the memory card to be interfaced to the microcontroller in order to expand microcontroller memory.
To enable serial communication between the microcontroller and the memory card it is necessary to adjust their voltage levels.
Memory card is powered with the 3.3V power supply voltage (VCC-MMC) generated by the REG1 voltage regulator, whereas the
value of the microcontroller power suplly voltage is 5V (VCC). A bus transceiver 74LVCC3245 is used here to adjust these voltage
levels. In addition, in order to establish communication between memory card and microcontroller, it is necessary to set switches 6, 7
and 8 on the DIP switch SW12 as well as switches 1 and 2 on the DIP switch SW13 to the ON position.
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: MMC/SD connector and microcontroller connection schematic
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: MMC/SD memory card
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: MMC/SD connector