13 votes
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What are left justified and right justified ADC results?

On this processor, the register that holds the conversion result is 16 bits wide. A right-justified result means that bits [(N-1):0] (where N is the number of bits of precision) of the register ...
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  • 316
12 votes
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Defining the heap and stack size for an ARM Cortex-M4 microcontroller?

Stack and heap are software concepts, not hardware concepts. What the hardware provides is memory. Defining zones of memory, one of which is called “stack” and one of which is called “heap”, is a ...
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11 votes

Why are typical UART baud rates not in multiples of 1000?

This goes way, way back to the Bell 103 modem from 1962. It operated at 300 bits per second for reasons deriving from the use of audio frequency-shift keying to modulate data; the frequencies ...
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  • 335
11 votes
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How do Thumb instructions compare to ARM instructions for performance?

In General THUMB instructions aren't to my knowledge intrinsically slower than ARM instructions, but rather are more limited in capability. If your code only needs the functionality of THUMB ...
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  • 296
9 votes
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Do "analog FPGAs" exist?

There are many chips that can be configured by choices made in software, which then have a perfectly analogue behaviour that gets altered. Blocks that work like that go from Analogue Switch arrays ...
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  • 381
7 votes
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How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?

This works for me with Linux 3.9.0 on an x86_64 architecture. ...
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  • 1,072
7 votes
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How fast should I sample with a logic analyzer?

The least you can do is given by Shannon-Nyquist theorem: to be able to read a signal, you shall sample at least twice its frequency. Here, you can sample at 20MS/s (Mega sample per second). ...
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  • 331
7 votes
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In a device tree for AM335x, how do I know what pinctrl values to use?

To update your .dts file (that includes the file am335x-bone-common.dtsi) for a pinmux assignment, consult the datasheet to determine which pin(s) are assigned to a function. This is in section 4.3 (...
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7 votes
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Saving RAM Memory when writing to 2K page size NAND flash

You don't need to fill the page register all in one go. You begin a page write (i.e. the "Page Program" operation) by writing the Serial Data Input command (0x80), ...
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  • 1,072
7 votes

Defining the heap and stack size for an ARM Cortex-M4 microcontroller?

The sizes of the stack and heap are defined by your application, not anywhere in the microcontroller's datasheet. The stack The stack is used to store the values of local variables inside of ...
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  • 316
7 votes

Flash Corruption - Power Supply or X-ray Radiation?

You should definitely consider X-rays as a possible source. An erased flash is full of 1s. Programming a flash is full of 0s. Over time, or under some stress, flash components may lose their gate ...
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  • 331
6 votes
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How fast movement (cycles/s) can I reliably read with PSoC4 quadrature decoder?

Quadrature decoder Looking at the PSoC 4 TCPWM datasheet the maximum operating frequency of the counter block is 48MHz, with a counter resolution of 21ns. Assuming that you have a high resolution ...
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6 votes
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How can I increase my processor's ADC resolution?

You can increase the effective resolution by intentionally oversampling the input signal. Here is brief summary of the idea from an application note on the topic provided by Atmel: The theory ...
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6 votes
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What IPC mechanisms exist for the i.MX 7 (or i.MX 6) multi-core processors?

The generic term for multi-core systems that run different kernels (or bare metal code) on different cores is Asymmetric multi-processing (AMP). Other related terms are Heterogeneous Computing, which ...
6 votes
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What is the behavior of unpowered FPGA pins on I2C bus?

It does, unfortunately depend a little on the FPGA itself. But most cases that will probably not work, unfortunately. In many logic chips with programmable I/O type pins, the final stage looks a bit ...
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  • 381
5 votes
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How to convert ASCII to binary to facilitate a UART to SPI bridge for an MSP430?

The input from the PC is a character, i.e. an ASCII-value. To understand how this is saved, have a look at the ASCII-table. The numbers '0' to '9' are represented by the ASCII-codes ...
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  • 166
5 votes
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Why are words bit-shifted for an Atmel SAM4S SPI slave?

This is due to the design of their SPI peripheral. In slave mode, the shift register is shifted each SPCK (assuming NSS is low ...
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  • 1,072
5 votes

Can an embedded system be designed to support electrical manufacturing testing?

I have done something similar with a small 8-bit microcontroller in a medical device. The factory had two pieces of firmware: First, factory test firmware is downloaded. It has the algorithms for ...
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  • 1,045
5 votes

Defining the heap and stack size for an ARM Cortex-M4 microcontroller?

In addition to the other answers, I'd like to add that when carving up RAM between stack and heap space, that you also need to consider the space for static non-constant data (e.g. file globals, ...
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  • 296
5 votes
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Is it possible to read a USB port directly?

No, at least not in any remotely modern version of Windows. Accessing hardware directly requires kernel privilege level, which ordinary application programs don't have. Think about it. It has to be ...
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4 votes
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How can I determine the code changes in an Atmel ASF update?

I think what you're looking for is the ASF Conversion Wizard. According to the linked page, this wizard is supposed to be launched whenever the ASF version changes. If is not launching for you, you ...
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4 votes
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What is the need of having a separate flag as Auxiliary carry in microprocessor 8085?

It is used for BCD arithmetic. Each decimal requires 4 bits.
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  • 356
4 votes
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What needs to be considered when configuring the clock system for a MSP430F5xxx micro-controller?

It depends a bit on the quality you expect from some of the peripherals and what their qualities are at given clock speeds. Will you want a very high speed SPI interface and can this specific chip ...
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