Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [embedded-systems]

Computer hardware and software which forms a component of some larger system. They are expected to perform functions with relation time constrains, without human intervention. Embedded system can range from simple MP3 player to complex avionics system.

72 questions
13
votes
2 answers

Do "analog FPGAs" exist?

I am thinking on analog circuits, whose circuit design could be read (or, at least, significantly altered) from software. Do they already exist?
peterh
  • 2,419
  • 4
  • 28
  • 44
13
votes
2 answers

How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?

For an embedded Linux system, if I have two or more network interfaces, how do I ensure that they always get the same interface names every boot In other words, I want, for example, eth0 to always map to one physical Ethernet port, eth1 to the next,…
Patrick
  • 1,072
  • 6
  • 17
12
votes
1 answer

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

Why are typical baud rates not in multiples of 1000 instead of being in multiples of 300 i.e. 4800, 9600, 19200, 115200, etc...? Is there a mathematical or electrical reason behind this?
prasad
  • 481
  • 1
  • 3
  • 8
12
votes
1 answer

What are left justified and right justified ADC results?

The TI MSP430F20XX series has a 12-bit internal ADC output, which is right-justified. What is the difference between a left-justified output and a right-justified output? What are their pros and cons?
prasad
  • 481
  • 1
  • 3
  • 8
11
votes
1 answer

How do Thumb instructions compare to ARM instructions for performance?

A colleague mentioned that Thumb instructions were significantly slower than ARM instructions (this was for an AT91SAM7S32 processor). Is this true? What are the performance benefits of one instruction set over another?
Patrick
  • 1,072
  • 6
  • 17
11
votes
3 answers

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

I have been working on and off on small embedded systems project on and off. Some of these projects used an ARM Cortex-M4 base processor. In the project folder there is a startup.s file. Inside that file I noted the following two command…
Mahendra Gunawardena
  • 7,153
  • 5
  • 25
  • 65
11
votes
1 answer

How fast should I sample with a logic analyzer?

If I have a 10 MHz digital signal, how fast do I need to sample with a logic analyzer to avoid any bit errors? Does the minimum sample rate increase if I want to attach a protocol decoder (e.g. SPI)? I am aware of the Nyquist-Shannon sampling…
Patrick
  • 1,072
  • 6
  • 17
10
votes
1 answer

Saving RAM Memory when writing to 2K page size NAND flash

I am writing a driver for the Samsung K9WAG08U1D NAND flash chip. The specification of the memory chip mentions it has a page size of 2048 bytes (2kB). I am using a TI MSP430F2619 which has 4096 Bytes (4kB) of RAM. This means I need to allocate a 2k…
prasad
  • 481
  • 1
  • 3
  • 8
8
votes
3 answers

How do I know if I need a pull up or pull down resistor for a GPIO pin?

I've seen many microcontrollers use pull up or pull down resistors either as a setting for GPIO pins or as part of the hardware. How do I know if I need a pull up or pull down resistor for a GPIO pin and if I do, how do I know which is right for my…
Dom
  • 181
  • 1
  • 7
8
votes
3 answers

Flash Corruption - Power Supply or X-ray Radiation?

I work with a system in which the microcontroller is exposed to X-ray radiation from time to time. Exactly how much radiation is hard to say... we've never measured it. Anyway, we've seen a mysterious form of flash corruption on a small sample of…
Nick
8
votes
1 answer

How can I increase my processor's ADC resolution?

I have an Atmel SAM4S MCU with a 12-bit internal ADC. I would like to achieve 16-bit resolution at a sample rate of 500 Hz. The input to the ADC is fairly low-frequency (about 20 Hz max frequency content), and low noise (less than one 12-bit lsb…
Patrick
  • 1,072
  • 6
  • 17
8
votes
1 answer

Is there an FPGA which could "re-wire" itself on the need?

For example, if there is many floating point operations, it could "rewire" the area of some of its integer units to handle floating point instructions, and vice versa. Or if there isn't too many calculations, but there is many I/O need, it could…
peterh
  • 2,419
  • 4
  • 28
  • 44
8
votes
2 answers

What does a Sad Face on a circuit board mean?

I have a Fisher and Paykel Washing Machine (model number WL80T65C, well past warranty) which got rained on (a lot) and one of the capacitors blew up. I've done an amateur replacement of the capacitor which might work but when taking the circuit…
Dave
  • 191
  • 1
  • 4
7
votes
1 answer

What needs to be considered when configuring the clock system for a MSP430F5xxx micro-controller?

I need to configure the clock systems for a MSP430F5528 microcontroller. The current development board has a 24MHZ crystal attach to XT2 pins (XT2IN/XT2OUT). The current design will need to support the follow peripherals. UART ADC SPI Timers Few…
Mahendra Gunawardena
  • 7,153
  • 5
  • 25
  • 65
7
votes
1 answer

What IPC mechanisms exist for the i.MX 7 (or i.MX 6) multi-core processors?

I'm considering using the i.MX 7 processor for a new design. The overall architecture appears to be similar to the i.MX 6, at least from comparing the block diagrams. What mechanisms exist for communication between the Cortex-M4 core and the…
Patrick
  • 1,072
  • 6
  • 17
1
2 3 4 5