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This is a 8-bit SRAM project and i had spent two hours on it. Function: Its has six signals(r/w Datain A1 A2 A3 Dataout(LED showed)) and each signal has three modes--high/pulse/low, except r/w(because it only in heigh or low that enable the ram store data or data out), u can store data or read data by turning switch on/off.
#Conditions(or u could seen my "SRAM cell" project) : if r/w=0→read, else write;A1 A2 A3 are inputs of 3-bit to 8-bit decoder which is used to select ram cell(NOR →left to right: D0......D7).
#Layout: left→vsource and five switches including r/w , Datain , A1, A2 and A3. Middle→memory cells (cross coupling NOR --upper row show memory state and in there you will seen two rows numbers, and you need the second one after you run it) and control logic gates. Right→a Decoder, another four switches uesd to write data and choose ram cells by hands.
#Operation: turning A1A2A3 switches to voltage mode(connected with three switches on the right),according to r/w u can store or read data. Be careful, when you store data, you should make r/w=0 before you turning address switches. Because if r/w=1, some memory cells will change while you turning address switches. If u want to read data in cycle just turning left address switches to pulse mode, and the LED will show the result from D7 to D0 again and again!
#Original state of rams maybe shows 2.5 or 2.49 voltage means high-impedance state. So you need write it and this is why SRAM will lose data after power off!
#You can delete OR gates and add other 7 LEDs to each column(one column is a ram cell which starts at the third column of layout), then connected them to the AND gates(the seventh row). An example like this: After running it, make r/w=1, Datain=1, address switches in pulse mode, then after 8 clock, make r/w=0, you will seen the LED lights up from right to left in cycle.
Ok, just try it and do it! Enjoy yourself!
Understand not, please tell me!
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