Questions tagged [memory]

Consider instead more specific tags, e.g., dram, sram, flash

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DDR UDQS and LDQS into one DQS controller

I have one x16 memory chip () that has two Data Strobe pairs (UDQS and LDQS), on the other hand, I have arm chip (i.MX6 ULZ) that has one Data Strobe pair (DQS). Is there any way of connecting them, I'...
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7answers
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Need a non-volatile memory IC with near unlimited read/write operations capability

I need a memory solution which is going to be used to keep track of an accumulated count on a micro-controller based project. By accumulated count, I mean to say that the micro-controller uses this ...
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1answer
323 views

Causes for Double Bit error

If I have a 1 Gb memory with EDAC for single bit correction for a critical application, what could cause a double bit error in this memory? Provided that the queues never get out of sync which causes ...
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3answers
258 views

Problems with understanding memory map STM32F446RE

I have a problem with the understanding of the memory map of the STM32F446RE. In the Datasheet is the system memory (0x1FFF0000 - 0x1FFF7A0F) 30,51kb big. But in the AN2606 the system memory is ...
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2answers
625 views

STM32 Memory Alignment unclear

As I'm reading the Mastering STM32 Book, I came across this graphic describing the memory map So what I'm trying to figure out is whether my understanding of memory is wrong, or if the graphic is. ...
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40 views

If the Sense Amplifiers structure is the same as an SRAM cell's, why the differential voltage on the bit line gets amplified?

source How you can see the structure with 6 transistors of a Sense Amplifier (SA) is the same as a SRAM cell, but this latter causes a little variation on the bitline voltage that the SA will amplify....
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1answer
51 views

External bus interfacing

This lab requires us to extend the memory and I/O ports on our µPad using our EBI backpack. What I'm confused about is how the fully address decoded SRAM will differ from the partially addressed i/o ...
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5answers
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Heap allocation on a microcontroller

I'm working on STM32F303VC. How does the heap allocation work? When I declare the arrays outside main() it allocates them on the heap - SRAM - 0x2000000 and forth in this MCU. But what determines the ...
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1answer
177 views

Purpose of enablers

I was reading the following book: But How Do It Know? The Basic Principles of Computers for Everyone I learnt that a memory bit ( a special wiring between 4 NAND gates) helps the computer remember ...
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1answer
92 views

What are the parameters I should consider while selecting a Memory IC? [closed]

I have a Microcontroller which needs to be connected to a memory using SPI Interface. What are the major parameters that I have to consider while choosing a Flash IC?
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1answer
105 views

Assembly language, accessing bytes of memory

I have some memory address 0x00000100 that I want to read from. The lower 4 bits read from this address indicates the states of 4 buttons - So bit 0 shows the state of button 0, bit 1 shows the state ...
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135 views

STM32 with Winbond W25Q80DV Write Data Issue

I am trying to store data in SPI FLASH MEMORY of WINBOND W25Q80DV. I am able to read status registers and manufacturer ID successfully but can't able to write data into it. The procedure I followed: ...
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1answer
1k views

gcc __attribute__ section not working?

I'm working on a Zynq Ultrascale+ MPSoC and trying to play around with the on and off chip memories. In the following program, I'm trying to place only variable 'x' into OCM (on-chip-memory) where ...
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3answers
2k views

What information exactly does an instruction cache store?

Processors use both data and instruction caches in order to reduce the number of slow accesses to main memory. However, while it is clear to me that the data cache's purpose is to store frequently ...
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1answer
64 views

How do I produce WE in this diagram?

I have designed a memory system that has 10KB ROM followed by 6KB of RAM. The ROM begins at 0000H. I had to use two 4K x 8bit ROMs and one 2K x 8 bit ROM. I also have to use one 2K x 8bit RAM and a 4K ...
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2answers
343 views

How can I determine how much memory a function occupies?

How can I view how much program memory a function is occupying ? I am currently at 95% program memory usage and do not have a licence to enable optimization. I am looking to find out which functions ...
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707 views

Why have apparent memory bitflips in non-ECC memory not increased?

Back in the early 2000s I remember asking about why it was so important that servers use ECC memory. The prevailing wisdom at the time was that systems with lots of RAM would be, statistically, more ...
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1answer
147 views

Address decoding different bank sizes in 64K memory

I'm doing a small Motorola 6809-based computer project, and since I'm a bit rusty when it comes to boolean algebra I'm wondering if I'm doing my address decoding a bit too complicated for my simple ...
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2answers
138 views

I've seen many conflicting answers online: For optical storage, does a pit represent a '1' bit or does a land represent a '1' bit?

I've seen many conflicting answers online so: When reading an optical disk, which one of these is true: A 'pit' represents 1 and a 'land' represents 0 or A 'pit' represents 0 and a 'land' ...
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1answer
74 views

Chaging EA/VPP by software on Intel MCS-51/8051

I'm designing a circuit that uses the combined Program/Data bus from Intel MSC-51 as advantage. By the MCS-51 specification it has an internal 4K ROM and a EA/VPP pin that if set to high will access ...
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1answer
13 views

Is it possible to add a UID to M45PE10-VMN6?

Is it possible to add a UID to p/n M45PE10-VMN6 ? We need to add this security feature to these chips, but I am assuming it needed to be done at factory. Originally we could have purchased p/n ...
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1answer
37 views

Can more than one memory device transmit on the data bus at once?

I know that in general only one device can transmit over the bus at once, but if they are all memory devices, can they act as one? I have four 256x8 chips, which I think means that I have 256 cells ...
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2answers
206 views

Interfacing 16-bit SRAM/MRAM with Arduino Mega

I a looking to interface a MR2A16A 4Mb 16-bit MRAM with an Arduino Mega. I am new to interfacing with memory chips and would like some advice from someone more experienced than myself. I am not ...
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1answer
81 views

Reading memory array

im new to memory cells. I have taken the below image from a video, i wanted to ask in the video he explains that the MUX can select 8 bits, but how is this even possible? The output of a MUX is always ...
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1answer
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Reading a MD25Q128SIG SPI flash memory with raspberry pi

I'm trying to read a MD25Q128SIG SPI flash memory with my raspberry pi, you can find its datasheet here: http://www.firstjit.com/Uploadfiles/20160121152131319.pdf Here are raspberry pi pinouts: Here ...
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8answers
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What prevents the construction of a CPU with all necessary memory represented in registers? [duplicate]

Modern CPUs employ a hierarchy of memory technologies. Registers, built into the chip have the lowest access times, but are expensive and volatile. Cache is a middle-man between RAM and registers to ...
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2answers
139 views

Core rope rom not working

I am trying to make my own core rope rom, according to the link. I have 15mm ferrite cores, which I wound about 30 times with 1mm magnet wire. I thread the primary ( also 1mm wire) through one of ...
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4answers
2k views

How can we determine memory usage of a microcontroller

How can we determine how much memory is being used, or will be used by firmware in a microcontroller? What tools can support this? Generally we don't use dynamic memory in embedded systems, but how ...
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2answers
2k views

How to write STM32F4 OTP Area

I am reading the reference manual page 75 that shows the flash memory organization of STM32F4 MCUs. There is an OTP area of 528 Bytes in it as shown in the image: Is it possible to write on this OTP ...
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1answer
314 views

How to increase memory on the FPGA board?

Situation I'm running a driver code driver.cc on the FPGA board (PYNQ-Z1) but it gives an error in the middle of the code where the code calls to ...
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0answers
24 views

Can FOTA be performed by changing the execution point of the code i.e, changing the program counter in lpc1759

For FOTA can we divide the memory into two blocks, eg : block A and block B. And whenever there is a new version of firmware detected, we shall change the execution point of the code. Is this ...
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1answer
234 views

Is a multiplexer needed to read from memory

we need to enable a register to write into that register, which is done using a decoder. even if we enable 1 register using decoder, given that RD(bar) is 0, all registers can still produce an output. ...
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185 views

How to use Altium Multi-Board to define SODIMM board and socket connections?

I am attempting to use Altium 18.1.9's new "Multi-Board" feature to connect a 200-pin SODIMM board ---> to a SODIMM socket connector ---> on my mainboard PCB. This Altium article is just about the ...
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2answers
115 views

Maximum cells in a row in a SRAM memory array

I was considering designing an SRAM memory array. For my design to be useful in a certain system, I need to have several cells in a row (e.g. 1024, 2048). In textbooks I have seen examples of arrays ...
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2answers
609 views

What does the number of “ single-word instructions ” mean on a MCU's memory specifications?

I have copied the following sentence from a PIC MCU datasheet: "PIC18(L)F26K22, PIC18(L)F46K22: 64 Kbytes of Flash Memory, up to 37,768 single-word instructions." the question is what does " 37,768 ...
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2answers
372 views

Designing a RAM, using 4x2 chips, with a 8 address capacity

This is a typical exam question, and I've seen some very helpful posts about, but I still have a lot of doubts. Given an integrated circuit of certain dimensions, for this example a 4x2, I have to ...
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2answers
259 views

What design differences make ram faster than ssd for read/write [closed]

I understand that RAM is connected directly to the CPU via a high bandwidth bus, and SSD is a peripheral, but my assumption is that there are also electrical design differences (e.g. memory cell ...
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2answers
172 views

Image memory on micro controller [closed]

I am trying to specify a microcontroller for a very simple task. All it does is show an image at boot up (which will most likely be black and white). The display itself is 240*240 and 12bit color ...
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1answer
299 views

How to write more than one page at once in Winbond W25Q32JV

I am using Eclipse IDE for firmware development. I am using Quectel MC60 module with Winbond W25Q32JV (4 MB memory). The thing is that I am able to read/write single page. I am facing issue with ...
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0answers
59 views

How is CAM implemented?

I have a book statement: A content addressable memory is a circuit that combines comparison and storage in a single device. I want to know how this is implemented in real world? Sounds like an ...
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1answer
79 views

Commercial SRAM with separate power supply for the core and peripheral?

Are there commercial SRAMs available with a separate power supply for the core transistors (6T) and a separate supply for the remaining circuitry such as the sense amps, write drivers, etc? I believe ...
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3answers
379 views

Embedded Firmware Question - Memory dump

Ok so the back story is this. I landed an online code interview with a company that shall remain nameless. I know I am not ready for a job there but I was basically given the chance by an insider. ...
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1answer
2k views

NOR Flash Memory Full chip vs Block vs Sector Erase

I am trying to use a NOR flash memory device: SST25VF016B (with STM32 discoveryboard F407VG). However, I am confused on some terms on their datasheet. You can find the datasheet here: https://www.elfa....
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2answers
2k views

Finding the address of structure knowing the address of one of it's members in C

This sounds like a little too far fetched, but is there any possibility to find the address of a structure, if the address of one of it's members is known? The struct itself contains different data ...
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3answers
95 views

Is memory possible without a flip flop circuit?

All the memory circuits I've seen use some form of flip-flop/feedback mechanism to store a value. Is this the only circuit design that can store a value? Is there anyway to create memory without a ...
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2answers
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Data Strobe in DDR memory

In DDR3 memory there is a signal called DQS that I have several question about. What is DQS abbreviated for? specially Q What is the purpose of data strobe in DRAM and why not use simple clock. Is ...
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1answer
206 views

How do memory seats keep track of their position?

I was wondering how do memory seats keep track of their position. Since this kind of equipment existed in 1990's cars, it must be simple yet ingenious. I have been thinking about this for quite a time ...
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1answer
123 views

Can a computer increase its memory in machine cycle? [closed]

For my college assignment, one of the question asks to explain how a computer increases its memory in machine cycle. I have searched and so far I have found that a computer can't increase it's own ...
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1answer
62 views

What is address allocation of memory register? [closed]

What is ment by address allocation of memory register in microprocessor and memory topic or in computer architecture? Memory chips are have no processing elements(passive elements). How memory chips ...
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2answers
514 views

Does pin A15 on a Z80 tell if the CPU is addressing ROM or RAM?

I am designing a simple, hobbyist single board computer similar to an Arduino using a Z80 CPU. The trouble I am running into is how the CPU addresses memory. I know that the Z80 uses pins A0-A15 to ...

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