DDR SDRAM is a dynamic ram standard that is designed to provide high memory depth and bandwidth. This section will provide the basic DDR SDRAM background necessary to effectively use the TM-4`s memory subsystem. In particular the memory organization will be presented, followed by a description of how both reads and writes are performed. In a DDR S
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DRAM dimm there are usually two memory chips connected in parallel, with only their chip enable signals being unique. This configuration allows the two chips to share address and data lines. By selectively asserting only one chip enable single at a time, this configuration allows twice the memory depth compared with only a signal chip. The highest level of the memory addressing hierarchy controls these chip enable signals. This addressing level is called the chip selects. The remaining three addressing levels all take place within a single memory chip. Figure 1 shows a simplified block diagram of the internals of a DDR SDRAM memory chip. At the core of the memory chip are four 2D memory array banks. Each of these memory banks is addressed by both a row and column address. To understand why this memory structure was selected it is necessary to first understand the process of reading from one of the 2D memory arrays. To read from the 2D memory array involves several steps. The first step involves selecting which row in the memory array to address. This is accomplished by issuing an ACTIVE command to the memory. This results in the memory array outputing an entire row of data via the sense amplifiers, shown in figure 1. At this point the memory chip is ready to accept read commands. These read commands include a column address, which is decoded and used to select which piece of data, currently outputted by the sense...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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