embedded

问题 I’ve just cross-compiled QT 5.2.1 for ARM and I am using it on a TI AM335x EVM (Starter Kit) board. I’de like to use the eglfs platform, but unluckily it shows some artifacts on the screen… I just made a simple program for showing the problem and captured some photos of my screen. The program basically draws a set of vertical black and white lines (alternated). If I run QT on platform linuxfb (that is I launch my program passing “-platform linuxfb” on command line) then the software works

问题 I am using an STM32 micrcocontroller to interface an SD card memory using the SPI peripheral. I have done tests with 2Gb , 4Gb , 8Gb and 16Gb SanDisk cards. When I perform a reset with the 2Gb and 8Gb cards , nothing happens and I keep going with my tests. However, with 4Gb and 16Gb , once the reset is performed intialization fails . In fact , at the first insert in the SD slot , these cards are quite good initialized but one I perform the reset it does'nt pass. When I tried to debug this

问题 My question is related to this one : c define arrays in struct with different sizes However, I do NOT want to use dynamic allocation (embedded target). Problem recap : In C , I want to have two versions of the same structure, each one with a different size for its static arrays. Both the structures will be used by the same functions through pointer parameter. typedef struct { short isLarge; //set 0 at initialization short array[SIZE_A]; //more arrays } doc_t; typedef struct { short isLarge; /

问题 I have a real-time embedded app with the major cycle running at 10KHz. It runs on a TI TMS320C configured to boot from flash. I recently added an initialized array to a source file, and all of a sudden the timing is screwed up (in a way too complex to explain well - essentially a serial port write is no longer completing on time.) The things about this that baffle me: I'm not even accessing the new data , just declaring an initialized array. It is size dependant - the problem only appears if

问题 I am trying to interface a contact-less smart card reader over UART (usbserial) using termios framework under Linux. The code works fine on the PC, but when I cross-compile and try it out on an ARM9 target, it is able to open the device and even writing the command to the device, but the read command blocks indefinitely. Here is the code snippet : int mifare_rdr_init(struct mifare_1K * ptr, char *rdr_devnode) { bzero(ptr, sizeof(struct mifare_1K)); // zero the entire structure // open serial

问题 I have to serve two masters. One project which is expected to split in two after v1.0. It initially was a straightforward embedded project coded in C using FreeRTOS. It till could be until v1.0. Afterwards, one master says we must use QNX to please a partner or lose a deal while another says that we must use J/XFS (Java extension for financial services) or lose another deal. QNX doesn't exactly seem bustling with support for Java. The best that I can find is this link, but t's hardly official

问题 Few days back i had an interview but, still I am searching for the answer. I would like to understand the significance of using volatile keyword. Find the code below: Two different scenario. //project1 //File1.c int abc;//Global variable /*And this variable is getting used in some other files too.*/ if(abc == 3) //Say { printf("abc == 3"); } else { printf("abc != 3"); } /*So if or else part will not be optimized because "abc" can not be predicted, the value can chage at any point of time */ /

问题 Summary My aim is to control the GPIO pins in Peppermint 4 Linux (Kernel version 3.8.0) on an Intel motherboard (NM70 chipset with C1037U processor). I'm debugging issues I'm having using the sysfs interface and am trying to understand the conditions where /sys/kernel/debug/gpio would be empty? When attempting to export pins 0 to 255 by echo XX > /sys/class/gpio/export for XX from 0 to 255, I get the following error message echo: write error: No such device Under what conditions would /sys

问题 While reading an answer on what all stuff the threads share I stumbled upon the term "call stack".While I am aware of the fact that threads have their own stack which they dont share with other threads,I am not understanding what a call stack would mean with respect to a thread. I have seen some answers but they were not very clear. Please clarify what a call stack means and how it differs from stack in the context of multitasking. Regards 回答1: Please clarify what a call stack means and how

问题 We have a small embedded system without any video or serial ports (i.e. we can't output text via printf). We would like to track the progress of our code through the initialization sequence. Is there some simple things we can do to help with this. It is not running any OS, and the hardware platform is somewhat customizable. 回答1: The simplest most scalable solution are state LEDs. Toggle LEDs based on actions, either in binary form or when certain actions occur if you can narrow your focus.