Problems with EE homework dealing with Octal D-FF and D Latch

[s w]

Homework Statement

Show the timing diagrams of the input bus and control inputs so the D Flip Flop has the value AA and the D-Latch has the value 55.
[PLAIN]http://img89.imageshack.us/img89/5047/babykg.jpg

The timing diagram consists of all the inputs, OE1, WR1, OE2, and WR2.

Homework Equations

NONE

The Attempt at a Solution

I mainly don't understand the purpose of OEN. I know that the latch will output the input when G is 1, and the flip flop will output on rising edge, but I honestly do not know how to store the data. I know that I must first load 55 into the flip flop, then pass that to the latch and then load in the AA but I am unsure how to actually load the information in. I assume it deals with OEN but I have not found a good explanation for that.

 

[berkeman]

Homework Statement

Show the timing diagrams of the input bus and control inputs so the D Flip Flop has the value AA and the D-Latch has the value 55.
[PLAIN]http://img89.imageshack.us/img89/5047/babykg.jpg

The timing diagram consists of all the inputs, OE1, WR1, OE2, and WR2.

Homework Equations

NONE

The Attempt at a Solution

I mainly don't understand the purpose of OEN. I know that the latch will output the input when G is 1, and the flip flop will output on rising edge, but I honestly do not know how to store the data. I know that I must first load 55 into the flip flop, then pass that to the latch and then load in the AA but I am unsure how to actually load the information in. I assume it deals with OEN but I have not found a good explanation for that.

OEN is just the Output Enable. From the description of the problem, I would think you could keep the outputs enabled all the time for this problem. If you had two chips' outputs connected together, both feeding into one other chip's inputs, then you would need to control the OEN inputs of the two chips to keep them from fighting each other on their outputs. But as this circuit is just connected 1-to-1, I think you can just keep the OENs asserted.

 

[s w]

Thanks for the reply. I think I figured out multiple ways to do it actually. Like you said, I could keep OEN at 0 all the time, well actually in this case wouldn't it be '1' since there is the not on the OEN?? Well, if I kept OEN enabled then I would just set G to 0 once it has the 55 loaded into it. Or I could keep G at 1 and then change the OEN1 to disabled once the 55 is loaded into the latch. Is this correct?

Actually I really want to know is, should OE1 and OE2 be 1 or 0 for this problem, given the 'not'.

 

[berkeman]

Thanks for the reply. I think I figured out multiple ways to do it actually. Like you said, I could keep OEN at 0 all the time, well actually in this case wouldn't it be '1' since there is the not on the OEN?? Well, if I kept OEN enabled then I would just set G to 0 once it has the 55 loaded into it. Or I could keep G at 1 and then change the OEN1 to disabled once the 55 is loaded into the latch. Is this correct?

Actually I really want to know is, should OE1 and OE2 be 1 or 0 for this problem, given the 'not'.

The circle at the input of the chip schematic figure means that the input is active low, so drive both low to enable their outputs.

 

[DeeNos]

I understand that learning new concepts and applying them can be challenging. In this case, it seems like you are struggling with understanding the purpose of the OEN input and how to properly load data into the flip flop and latch.

The OEN input, also known as the Output Enable input, is used to control when the output of the flip flop or latch is enabled. When OEN is high, the output of the flip flop or latch will be enabled, and when it is low, the output will be disabled. This is important because it allows us to control when the stored data is passed to the output.

To properly load data into the flip flop and latch, you will need to follow these steps:
1. Set OEN to low to disable the output.
2. Set the control inputs, WR1 and WR2, to the desired values to load data into the flip flop and latch.
3. Set the input bus to the desired data value (in this case, 55 for the latch and AA for the flip flop).
4. On the rising edge of the clock, set WR1 and WR2 to high to load the data into the flip flop and latch.
5. Once the data has been loaded, set OEN to high to enable the output. This will pass the stored data to the output.

I hope this explanation helps you understand how to properly load data into the flip flop and latch. Remember to always refer to your textbook or class notes for a more detailed explanation and practice problems to solidify your understanding. Keep up the good work!