Product manual

-AXIMUM LOGIC  OUTPUT VOLTAGE 6/,   6

-INIMUM REQUIRED LOGIC  INPUT VOLTAGE 6)(   6

-AXIMUM LOGIC  INPUT VOLTAGE   6

-AXIMUM REQUIRED LOGIC  INPUT VOLTAGE 6),   6

7HEN CONNECTED TO A 0)# MICROCONTROLLER THE OUTPUT VOLTAGE  6 OF THE

3$ CARD IS ENOUGH TO DRIVE THE INPUT CIRCUIT OF THE MICROCONTROLLER 4HE TYPICAL LOGIC

 OUTPUT VOLTAGE OF A 0)# MICROCONTROLLER PIN IS  6 AND THIS IS TOO HIGH WHEN

APPLIED AS AN INPUT TO A MICROCONTROLLER PIN WHERE THE MAXIMUM VOLTAGE SHOULD NOT

EXCEED  6 !S A RESULT OF THIS IT IS REQUIRED TO USE RESISTORS AT THE INPUTS OF THE

3$ CARD TO LOWER THE INPUT VOLTAGE &IGURE  SHOWS A TYPICAL 3$ CARD INTERFACE

TO A 0)# MICROCONTROLLER )N THIS FIGURE  AND + RESISTORS ARE USED AS A

POTENTIAL DIVIDER CIRCUIT TO LOWER THE 3$ CARD INPUT VOLTAGE TO APPROXIMATELY  6

AS SHOWN BELOW

3$ CARD INPUT VOLTAGE   6 s  +   +   +   6

)N &IGURE  THE 3$ CARD IS CONNECTED TO 0/24# PINS OF THE MICROCONTROLLER AS

FOLLOWS

SD Card Pin Microcontroller Pin

CS RC2

CLK RC3

DO RC4

DI RC5

4HIS IS THE RECOMMENDED CONNECTION BECAUSE IT USES THE 30) "US PORT PINS OF THE

MICROCONTROLLER 2# 2# AND 2#

Table 3.6: SD Card Input–Output Voltage Levels

Symbol Minimum Maximum

Logic 1 output voltage VOH

0.75

s Vdd

Logic 0 output voltage VOL

0.125

s Vdd

Logic 1 input voltage VIH

0.625

s Vdd Vdd  0.3

Logic 0 input voltage VIL

Vss  0.3

0.25

s Vdd

Memory Card 121