# Questions tagged [race-condition]

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### RS Latch: Signal behavior during transition from invalid to valid state

I have read a few of the posts here regarding race conditions as they pertain to the RS Latch, but they don't answer my specific question. I understand that if the latch is given an invalid input like ...
• 21
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### How do clock signal generators prevent race conditions?

With full understanding that wikipedia is not a completely reliable source, this wikipedia article explains that a clock signal prevents race conditions by making components update at the same time. ...
• 25
1 vote
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### How to consistently read two counter registers across PDEC and TCC on SAMD51

I am using the PDEC on a SAMD51 to read a quadrature encoder from a closed loop stepper motor which has 4000 encoder increments per rotation. The PDEC counter is only 16 bits wide, which would ...
2k views

### Does the master-slave JK flip-flop really solve the race condition?

The master-slave JK flip-flop is said to solve the problem of racing, as per many online resources that I've referred to. However, let's say that the initial state of the flip-flop is CLK = 0, J = 0, ...
72 views

### Why does this Verilog testbench not undergo a race condition?

This is the testbench in question: ...
• 131
1 vote
57 views

### How do I figure out if my Verilog code output was generated out of race condition?

Apart from physical observation, is there a way to know if my code will undergo a race condition? For example, the following code has a race condition because both ...
• 131
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### How do y1 and y2 take on two different values here? Can someone please explain the order of assignments?

The following code snippet is an example from a SNUG 2000 paper that explains race conditions. The explanation for the race condition is given below, but I do not understand it. How is y1 and y2 = 1 ...
• 859
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### Can a register remove the race condition in this case?

My book has this example of a race condtion: The race condition is: If D and CLK is 1, and CLK goes to zero, then we want the output Q to remain 1, however if the inverter is slow compared to the ...
• 299
565 views

### Lattice ICE40-LP1K 84-QFN SPI Flash Programming

I'm using ICE40-16-WLCSP-Eval-Kit as a reference design for the Lattice ICE40-LP1K 84-QFN which I'm going to use in the motherboard I'm designing. I did a little experiment with ICE40-16-WLCSP where I ...
• 1,077
322 views

### Will a synchronous circuit have a race condition if not all inputs arrive before the clock rising edge?

Suppose that the circuit has several inputs from an external circuit which do not have an effect until the clock next rise edge due to using synchronous flip-flops. If the external circuit sends ...
• 185
128 views

### Is more clock speed means higher risk to circuit can have race condition

It is a very simple question but it made me think. I have been working on finite state machines. I came to topic of finite state machines from combination circuits. In the book it says that sequential ...
317 views

### Latching Priority Encoder, circuit works but I don't trust it

I added a schematic even though the question is actually too simple for it. The datasheets for the devices are likely to be more revealing. The circuit is super simple. I have a 74HC148 priority ...
• 203
252 views

### Delaying clock pulses without adding (much) extra circuitry (CMOS)

I have a counter (74HC193) counting up with Qn outputs being decoded by a demultiplexer (74HC138). My clock pulses (CP) are no less than 100 microseconds long and the interval between them is always ...
• 203
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### Interaction beween DMA transmission complete and peripheral interrupts

I have two related questions regarding using DMA with an STM32 chip. I'm using STM32F031C6, but the answer should apply to other models. I setup the USART to issue a character match interrupt. I'm ...
446 views

### Verilog - use a clock signal as a value in its own procedural block

I tried synthesizing the following code and was surprised to see that it doesn't work (at least with Vivado 2017.2). ...
• 1,073
1 vote
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### When can the output of any flip flop (e.g., JK FF) be indeterminate?

I came across following problem: In an SR latch made by cross-coupling two NAND gates, if both S and R inputs are set to 0, then it will result in A. Q = 0, Q' = 1 B. Q = 1, Q' = 0 C. Q = ...
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### Is there possibility for a race condition in the following circuit?

On this wikipedia page, there is an example of a circuit which implements a D latch using NAND gates : Let's say the flip flop is initialized correctly (eg : Q = 0 and !Q = 1). If D = 1 and E = 0, ...
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### How do I avoid a race condition in SR latch?

I have designed an SR latch using Cd4001 NOR gate IC. When both S and R are low the circuit refuses to stay in previous state even though I am using appropriate dropping resistors. Is there any way to ...