VxWorks Embedded development system introductory basic concept learning

1.VxWorks applications

automation equipment, industrial control (good real-time), military equipment and consumer electronics.

2. Real-time sex

Real-time sex includes hard real-time, soft real-time. Hard real-time systems have a rigid, immutable deadlines that does not allow any errors that exceed deadlines. Soft real-time is a flexible and flexible, it can tolerate accidental time-out errors, the consequences of failure is not serious, for example, in the network only slightly reduced the system's throughput, and so on. In a word, the difference is whether all responses are done within the prescribed deadlines.

3. System structure

Features of the 4.BSP

(1) CPU initialization (2) memory controller initialization (3) serial port, network port, the initialization of the hard disk (4) Interrupt controller, clock and timer initialization

5.vxworks Image Type

There are four main types:

(1) Loadable: This vxworks operating system image containing the user program does not have the boot function, need to use bootrom through the network port or serial port to download to ram, more for debugging.

(2) Bootroom: Boot program, usually burned in ROM or flash, after power on to execute itself boot operating system. rom-based image includes Bootroom compressed bootloader and bootrom_uncmp uncompressed boot program. Power-up will boot from ROM, load VxWorks image to run in memory, similar to U-boot.

(3) Application of Vxworks_rom and vxworks_romcompress products, booting directly from ROM, including boot program and OS image, for the final product.

(4) The instruction portion of the rom-resident:image is run in ROM, and only the data segment is copied to RAM for the lower memory embedded processor.

6. What is Bootrom

VxWorks boot program, not BSP, similar to Uboot. Power on the first self-extracting, and then load the OS from the specified address, can be used to do the logo.

7. Development process

Set up development environment à kernel start code research à start vxworks minimum kernel, provide system clock and interrupt vector à use Tornado to debug à complete specific drive.

8.wind kernel

9.Vxworks There is no concept of process and thread, the task is the equivalent of a thread, and all threads have access to shared resources.

10.Vxworks Interrupt Handling

Interrupts preempt the highest priority task. ARM has a dedicated interrupt stack

You cannot call semaphores, you cannot call malloc (), you cannot call block functions such as the IO function, printf, to be as short as possible, to avoid floating-point operations, because of the slow running speed, you can use Logmsg.

11. Application Development

Inter-thread communication

Inter-mission communication means: Shared data structure, shared memory, Semaphore, message queue, pipeline, signal, socket communication.