Unused NOS Dynamic RAMs MHB, produced by Tesla, Czech Republic. Upward Pin Compatible with (16K Dynamic RAM). The price is for one IC (1 . Buy NTE ELECTRONICS NTE online at Newark element Buy your NTE from an authorized NTE ELECTRONICS distributor. TMS DRAM are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for TMS DRAM.

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What I would like to do is perform DMA to a Commodore 64’s internal memory which is a supported function of the computer. DRAMs are organized internally as a square matrix. Are you trying to monitor or share data with the other system?

MHB4164 Tesla 4164 64k X 1 Dram Dynamic RAM

On the left side of the matrix is a row selector, which basically consists of a large demultiplexer. Tue Jul 08, I’m quite a proficient programmer 30 years experience but my electrical knowledge is just a bit beyond basic but improving.

I have done quite a bit of Arduino projects previously. Along the bottom of the matrix are sense amplifiers which turn the slightly higher or lower voltage into a definite high or low signal, which is then fed back into each capacitor in a row to fully charge or discharge it again. I’m currently looking at an old circuit which uses a dram based ram network. There are some bus contention signals to take into account video chip access gets priority. The information of a DRAM must be refreshed after a few milliseconds.

The external device must respect the video chip accesses which are indicated by a signal line. This mod will make the chip look just like a ’64 chip to the system. Users browsing this forum: You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum.


Mon Jul eram, 3: You have to solder a short piece of wire between pins 1 and 16 of that chip these are the pins just left and right of the alignment notch on the chip. Perhaps you should start by explaining why you would want to.

org • View topic – dram refreshing!

From there, the columns are multiplexed down to one bit using the column address, and that’s the data drsm output by the chip. The input – also programs and data – will be loaded into the ram before the CPU can run this program. Although they are electrically and mechanically identical, every producer has his own system to mark the RAM chips.

The RAM in rdam is dynamic and is refreshed by another system so this would purely be bit addressing with an 8-bit data bus. The book itself explains how it all works, so there is a fantastic guide to solving your design there.

In other languages Deutsch. At the top of the matrix is a precharge circuit which charges each column to half the supply voltage; when each capacitor in a row is connected to a column line, it swings the voltage slightly higher or lower than half, depending on the bit stored in the capacitor.

I am fully aware that I might be asking the impossible but I’m sure there must be a way. Eight such chips in a row provide an 8-bit data bus and 64K bytes of memory. As also today 1464 the PCyou have to not only choose the appropriate memory size, but you also have to know where 41644 limit for the access time is. Robin Elvin 3. Building black plywood Habitrails”. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms drqm Service.

Post as a guest Name. It certainly makes no sense today as a storage device. The sram is The CPU can be halted and its bus lines put into a high impedance state so that an external device can access the memory.


While the preceding letters often hint to the producer, the following series of digits indicates the size and organisation of the memory. The computer’s CPU will be halted and tri-stated during this so I only have to share the bus with the video chip.

MHB Tesla 64k X 1 Dram Dynamic RAM | eBay

Sign up or log in Sign up using Google. Any ideas on how to achieve this would be helpful to get me started. Along each row are capacitors, with transistors to connect the capacitors to the columns when the row line is asserted. At the rates in question a cheap USB-based logic analyzer could probably capture everything that happens; it’s not entirely out of cram question that carefully written code could as well.

Retrieved from ” https: Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. Do you need to write or is snooping enough? The memory is constructed from DRAM chips of varying speeds the slowest of which are ns parts hence the requirement. At dran point, the whole row is refreshed. The bit address bus and 8-bit data bus are available to connect to.

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I can’t find a reference for the s right now, but I believe that a hardware refresh circuit would probably work better cram software, due to the load it would put on the processor.

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If you need one of the chips, you can also use a instead. Xram of these chips expandable by another 8 make up the main memory in the VIC Mon Jul 07,