DDR SDRAM and the TM-4

Posted on Feb 5, 2014

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

Click here to download the full size of the above Circuit.

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...

Visit page

Leave Comment

characters left:

Related Circuits

decoder circuit

As you can see from the article LPT port expander, this PPI-8255 is a general purpose I/O programmable function. But usually this IC are tired to the computer bus directly. Return to this idea,...

Build your own simple IC tester applied to standard TTL or CMOS IC

What is mean logic-1 or logic-0 Logic-1 and logic-0 strongly connection between the state at one moment and one condition. Logic-1 means any states are in the condition of high voltage close to Vcc...

Another kind of relay driver board used to utilize your old PC

This article means to utilize your old PC to be come a simple controller. Many old PC like 8088 type, 8086, 80286, 80386, or even 80486 already become an obsolete systems, since they can not run...

preamp circuit 3

During my Digital Projects Lab, the professor recommended I find a way to include more circuit level work into my project. To fulfill this, I decided to build a nice preamplifier which wouldinclude...

PIC dual Thermometer

This one is using a 16F876 PIC, MCP1047A temperature sensor ( X2 ), MCP1541 voltage reference and MCP6022A opamp. The display is a 2 row HD74780 based 2X16 char, SII L1652BIJ2 but any other display...

Expressive Arduino Midi Sequencer

This section of code outlines the main sequence of operation for the sequencer. First, a for loop is utilized to govern which step the sequencer is operating in. Within this loop, first an address...

led rf signal meter

This RF Wave Absorbion meter will detect signals between 10cms and 10m away all acording to the setting of the 22MegOhm gain adjustment potentialometer and the power of the transmitter. The RF...

Transmitting audio over laser or LED

Want to send your audio information via a light wave across the room I built this simple circuit with some modifications that transmits an audio signal via light. The signal simply amplitude...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

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....
Ultrasonic distance finder circuit

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....
Simple Metal detector circuit with CD4030

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....
Fully automatic watering circuit for flower pots

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....
Simple deep searching metal detector circuit

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....
Sub-Harmonic Bass Converter for Electric Guitars

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,....
Echo Depth Sounding Sonar for Boats

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....
100W HiFi Audio Amplifier Circuit

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....
Plant-Pot Water Level Indicator Circuit

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.....

Create NOW your QR MENU for your Restaurant / Hotel / Bar / Caffe,

Comprehensive ordering/paying features. fully personalized to suit your Business.

Update Anytime! Easy and Simple!

Popular Circuits

WinCircuit

WinCircuit is a software of realization of drawing of printed circuit in single or double layers....

FM Transmitter

Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter....

PCB Exposure Box with Countdown timer (ATMEGA8)

Four blacklight lamps, 15W each, emit radiation at the region of UVA, with a peak around 350nm...

RS-232 data buffer

This is a simple serial port buffer circuit I designed for a friend to speed up his SLIP...

Negative Voltage Reference Circuit

This circuit is a Adjustable voltage reference circuits, a voltage source which provides a...

Logochip Creative Works

There is something to be said for the processes of reducing a set of objects or functions down to...

maze robot sensor integration

This project was completed during a course on robotics taught by Prof. Dave Barret at Olin...

fet preamp

The PZP-1 Piezo Buffer is now available! The PZP-1 is a high impedance buffer preamp, using 100%...

plant watering watcher dry soil detector

The schematic shown here is a circuit of plant watering watcher or dry soil detector. The plants...

555 timer ic based simple servo

Servos became valuable products for any variety of plans, like robotics, automation or only...

TV to receive CBS-System Color (1951)

The color wheel and motor control are up to you. Yes, this is field-sequential color, not the...

SG3525A Pulse Width Modulator Control Circuits

This article describes an amplifier Audison LR604XR principle. The principle is simple there, we...