User Manual

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Q7’: Series output pin, connected to DS of another 74HC595 to connect multiple 74HC595s
in series
MR: Reset pin, active at low level; here it is directly connected to 5V.
SH_CP: Time sequence input of shift register. On the rising edge, the data in shift register
moves successively one bit, i.e. data in Q1 moves to Q2, and so forth. While on the
falling edge, the data in shift register remain unchanged.
ST_CP: Time sequence input of storage register. On the rising edge, data in the shift register
moves into memory register.
OE: Output enable pin, active at low level, connected to GND.
DS: Serial data input pin
VCC: Positive supply voltage
GND: Ground
In this experiment, connect ST_CP to Raspberry Pi GPIO1, SH_CP to GPIO2, and DS to GPIO0.
Input data in DS pin to the shift register when SH_CP (the clock input of the shift register) is
at the rising edge, and to the memory register when ST_CP (the clock input of the memory)
is at the rising edge. Then you can control the states of SH_CP and ST_CP via Raspberry Pi
GPIO to transform serial input data into parallel output data so as to save Raspberry Pi
GPIOs.