Serial ram avr

I've seen fairly cheap IC's that have up to 3 or 4 Megabits not quite enough for what you are wanting but there should be bigger ones around and combining it with shift registers. That way you'd only need 4 or 5 lines from the AVR to access the RAM because the FIFO does not need addressing information and the shift registers will take care of converting your serial data to parallel. Just read the data from the hard disk and write it to the FIFO.

Then, as you need data read it back from the FIFO. I use it in 64 pages of 32k x 8. Controlled with a PLD. One page register. I need the low power of SRAM. But for you it may be possible to use DRAM. Also controllable serially PLD. From what I've read, the best read: easiest to use ram for microcontroller use is "static column" ram salvaged from an old Amiga and maybe some other computers of that era.

It's not quite plug and play, but apparently is ridiculously easy to interface with. Unfortunately, it hasn't existed as a commercial product in over a decade, so its only real source now is either new old stock or salvaged chips. On a personal note, I remember it well Aeons ago, I actually doubled my Amiga 's ram from k to a meg by soldering identical ram chips onto the existing ones "piggyback style", with the select pins wired separately. Thanks for the pointers - I'll read a few datasheets and see what looks best.

It looks like FIFO may be the current way to go! Trouble with FIFO First In First Out ram is that once you read the data it is no longer contained in the memory well acutally it is but you can't get at it again. Indeed, there are many occasions when the master simply wants to prod the slave into giving up some data, and it does this by sending something — anything.

Like many things on microcontrollers, SPI is controlled through the cunning use of registers. Our focus here will be on using the AVR as a master device. All eight bits are used to configure the interface, and they are:. Set this to 1 to be Little-Endian if you roll that way or the slave device expects it. There are four modes:.

Its datasheet says the following:. How do you know? Back to the datasheet. It should show timing diagrams. Here are examples for our RAM chip:. See how the SCK line is low before everything starts in the input version? So the rising edge here is also the leading edge, meaning that we want mode 0, also known as 0,0 in many circles.

Change Password. These 8-pin low-power, high-performance SRAM devices have unlimited endurance and zero write times, making them ideal for applications involving continuous data transfer, buffering, data logging, audio, video, Internet, graphics and other math and data-intensive functions.

This device is significantly lower cost than other nonvolatile RAM devices, and the data is backed using an external battery. This 8-pin, SPI device supports unlimited instantaneous writes to the memory array, making it ideal in applications such as meters, data loggers, data recorders or black boxes.

These devices are available in Kbits and 1 Mbit densities. All rights reserved. We detect you are using an unsupported browser. For the best experience, please visit the site using Chrome, Firefox, Safari, or Edge.

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