The idea behind a positive edge detector is to delay the original signal by one clock cycle, take its inverse and perform a logicalANDwith the original signal. modulepos_edge_det(inputsig,// Input signal for which positive edge has to be detectedinputclk,// Input signal for clockoutputpe)...
1moduletop_module(2inputclk,3inputd,4outputq);56regp,n;7// A positive-edge triggered flip-flop8always@(posedgeclk)9p<=d^n;10// A negative-edge triggered flip-flop11always@(negedgeclk)12n<=d^p;13// Why does this work?14// After posedge clk, p changes to d^n. Thus q = (p^...
,我曾經討論過用Verilog實現Sobel edge dector的原理與方式,用的是DE2-70,但DE2畢竟是大家最熟悉,也最流行的平台,所以這次來看看如何在DE2實現Sobel edge detector。 在DE2平台所需做的修改 我以DE2 CD的DE2_CCD範例為藍本,使用130萬像素的TRDB-DC2為輸入,VGA為輸出,將Sobel edge detector加到DE2上。Sobel....
但用Verilog做影像處理,由於是real time,SDRAM只是frame buffer,可以看成是一個FIFO,影像不斷地從CMOS進來,經過SDRAM之後,不斷地從VGA出去,我們並無法使用記憶體位址的概念去存取每個pixel的RGB資訊,也無法建立一個二維array來存取,這是用Verilog做影像處理所面臨最大的挑戰。 Sobel Edge Detector 詳細的Sobel演算法流...
詳細的Sobel演算法流程,我就不再多談,請參考Sobel Edge Detector。下圖的Gx與Gy是Sobel edge detector在X方向與Y方向的kernel,將與P5這個pixel做convolution。 雖然是對P5運算,卻必須同時知道P1、P2、P3、P4、P6、P7、P8、P9的資訊,這在C不是問題,因為都在array內,只要改變一下array的index就可得到,但在Verilog...
For example, the design above represents a positive edge detector with inputs clock and signal which are evaluated at periodic intervals to find the outputpeas shown. Simulation allows us to view the timing diagram of related signals to understand how the design description in Verilog actually beha...
本文將DE2-70平台的DE2_70_TV的範例加上Sobel Edge Detector。 Introduction 使用環境:Quartus II 8.0 + DE2-70 (Cyclone II EP2C70F896C6N) DE2_70_TV與DE2_70_D5M_LTM的架構非常類似,都是以SDRAM當做frame buffer,所以若要加上演算法,基本上也是放在SDRAM之前做前處理,或者放在SDRAM之後做後處理。
r : Rising edge. Same as 01 f : Falling edge. Same as 10 p : Potential positive edge. Either 01 or 0x or x1 n : Potential negative edge. Either 10 or 1x or x0 Example 2x1 multiplexer (combinational ex) primitive mux(out, sel, a, b); output out; input sel, a, b; table...
The 1 clock cycle shift is made by using a positive edge-triggered flip-flop.The table shows the current counter state and the next state. The first column shows the clock divider output.Here, tp stands for time period of the clock, i.e. + 1 tp stands for the signal delayed by 1 ...
Example: This example uses the cross operator to model edge triggered events. (see note on page 3-66 for more information) Phase/Frequency Detector module pfd_cp(out, ref, vco); current out; voltage ref, vco; output out; input ref, vco; parameter iout = 100u; integer state; analog ...