Abstract: Introduced based on DSP the chip TMS320C32 imagery processing platform’s network test system, has given use special-purpose video input processing chip SAA711 and CPLD realizes the high speed continual video frequency frame gathering design mentality. Simultaneously has given this system in the embedded system based on the PPP agreement Internet connection method.
Key word: PCI main line; PPP agreement; DSP; VxWorks operating system; Embedded
In long-distance observation system, embedded system, because its stability and timeliness surpass the traditional platform to obtain the rapidly expand. This article proposed one kind take the DSP chip and VxWorks as operating system’s new embedded system design method.
1 test system principle of work
Shown in Figure 1 test system’s primary mission is uses DSP chip processing through the camera photography and the image which transforms after A/D. The overall system by the video frequency decoder, DSP and the PCI main line special-purpose chip is composed. The system through the PCI main line with the communications platform exchange data, simultaneously carries on the examination control through the network, shown in Figure 1 is its system diagram.
2 key designs and component choice
This system design’s key is the video frequency transaction card design, the video frequency examination card function generally is limited, cannot satisfy this project the demand, for this reason, the author has independently designed a video frequency examination card. Its structure diagram as shown in Figure 2.
2.1 TMS320C32 function characteristics
In this test system’s DSP chip selects T I company’s T M S 3 2 0 C 3 x serial productses, this component’s operating frequency is 40MHz; Uses the Harvard bus structure. And has the unique command system and the hardware while adds the operation; Gives extra 256k×32Bit FLASH, 2k×8Bit NVRAM and 256k×32Bit SRAM. This chip is simplifies in the TMS320C30 foundation comes, includes the TMS320C30 CPU essence.
The TMS320C32 major function is as follows:
* has the pre-computed course function;
* the serial interface transmission and the memory may support 8, 16, 32 data;
* may have the border interrupt and the level interrupt;
* may program the hypothesis interrupt by the user to the meter address;
* has the spatial waiting and the low power loss two power source mode of administration;
* has two DMA channels;
* the function formidable exterior memory interface both may satisfy the video frequency decoding connection 8 bit data the requests, and may realize the PCI connection 32 bit data high speed data transmissions;
* the nimble program load may realize in the system programs;
In the ordinary circumstances, between S5933 and the DSP hardware connection is using DSP read-write signal R/W, address strobe control signal IOSTRB, external instrumentation ready signal RDY and the partial address signal as well as S5933 FIFO status signal WRFULL carries on the simple succession and the logical combination, thus produces to the S5933 sur- bus interface read-write control signal.
2.2 other component’s choices
In this system’s CPLD chip selects ALTERA Corporation’s EPM9320RC208. Two group of frame memory A and B use two CY7C1049 chips which CYPRESS Corporation produces, this chip’s capacity for 512k×8bit, the access time does not surpass 15ns, can satisfy the image real-time gathering request. May complete the frame automatically through a CPLD interior’s pingpong stop-go control module the read-write two channel interface cut. But between DSP and the SAA7113 all control signal interface logic and the succession transform complete by CPLD, and programmable revision, thus enhanced system’s use flexibility and the reliability. Shown in Figure 3 is EPM9320RC208 and the CY7C1049 interface control functional block diagram.
PCI main line specific interface chip S5933 is one kind of function is formidable, and uses the nimble PCI bus control unit special-purpose chip, this chip conforms to the PCI local bus standard 2.1 editions, it already may realize the basic transmission as the PCI main line goal equipment; May also visit other PCI main line equipment as the PCI bus master equipment. The S5933 peak value transfer rate is 132Mbps 煟 Chang Can fools the school vast soil moisture 牎 8 stuffy ku to provide according to the line has 3 physics bus interface: The PCI bus interface, the sur- bus interface (ADD-ON BUS) as well as may elect NV memory interface.
The SAA7113 function realizes the analog picture A/D transformation. Between DSP and SAA7113 hardware interface control logic including two sub-modules: The frame image reads in the controller and the pingpong switch, these two kind of functions may complete together by CPLD.
In the video frequency card design, the power source module’s design is also essential, its immediate influence video frequency card is realizing finally with the steady operation.
This supervisory system uses TI Corporation’s TPS3307-33D to come as the power source to examine IC. This component’s Reset effective power source resetting voltage value definition is VDD=1.1V. TPS3307-33D may simultaneously monitor two kind of independent voltages, but may also control other one kind of voltage, this kind of voltage may adjust independently and is connected in the internal and the replacement logic circuit.
3 communications platform embedded system design
This design software system including first floor software and system software two parts, the first floor software is mainly DSP operating procedures and so on imagery processing algorithm as well as start, these procedures may compile under the CCS environment by the C language and carry on the assembly optimize, CCS is the DSP software movement environment which TI Corporation issued;
In the system software aspect, the difficulty which faces based on the PCI main line’s imagery processing system quite a lot, what the difficulty is biggest is the PCI actuation question.
3.1 system software’s designs
The system software may select take VxWorks as operating system’s embedded design method.
The VxWorks operating system’s integrated environment calls Tornado. The Tor-nado integration environment is a highly effective defined presente in figures and diagrams real-time application develops the platform, it including a set complete, measures the tool face embedded system’s development and the accent. The VxWorks merit is as follows:
(1) has well may the reduction;
(2) supports the application procedure the dynamic link and dynamic downloading;
(3) has the good compatibility;
(4) has the very high reliability and the stability;
(5) has the very good timeliness;
The VxWorks multi-duty mechanism the control uses the priority grab and the rotation dispatch mechanism to the duty, thus has guaranteed timeliness fully, and the available same hardware disposition satisfies the stronger timely request, in order to leave behind a bigger leeway using the development.
The PCI equipment has three physics storage space: Disposition space, memory space and I/O space. And the disposition space is the length is a 256 bytes section of continual space, spatial definition as shown in Figure 4, in the disposition space, the read-only space including equipment marking, the supplier code, revises the edition, the classified code as well as the first prize type. And the supplier code uses for the marking equipment supplier’s code; Equipment marking uses for to mark some special equipment; Revises the edition marking equipment’s edition number; The classified code uses for marking equipment’s type; But the first prize type uses for to mark a type as well as whether is the multi-purpose equipment. Except the supplier code outside, other field’s value may assign by the supplier.
The base register most important function assigns the PCI equipment’s system address space. In the base register, bit0 (most low position) may use for to mark is the memory space or the I/O address space. When the base register maps the memory space, bit0 is “0″, but when it maps the I/O address space, bit0 is “1″.
When actuates the PCI equipment, first is the PCI equipment’s search. The embedded operating system provides generally has the corresponding API function search. But in the VxWorks operating system, hoped remote lu Sang Mo煟 school vast Sang Lumu MuNiu Zheng Sangmang ning 煟 liang wisdom lie peaceful &pciBus &pciDevice,&pciFunc_ through function pciFindDevice 煟 school vast Sang Luzheng Niu Weimu to be possible to find the supplier code is PCI_VENDOR_ID, the equipment marking is PCI_DEVICE n (index 1) an equipment, and returned to the total wire size, the equipment number as well as the function number, then preserved separately in &pciBus, &pciDevice, &pci-Func.
Next is the PCI equipment’s disposition. The API function which provides through the operating system may visit the PCI equipment’s disposition space, thus completes the PCI equipment base register’s disposition, the interrupt disposition, as well as the ROM base register’s disposition, obtains the PCI memory space and the I/O address space mapping as well as the equipment interrupt number finally and so on. In the VxWorks operating system, visits PCI the equipment disposition space the API function to include: pciConfigOutLong and pciConfigInLong and so on, they may complete separately to the PCI equipment disposition space read-write operation.
Is compiles the different equipment’s initialization routine, the interrupt service as well as to the PCI equipment storage space access routine according to the PCI equipment’s disposition parameter.
3.2 remote controls and information link
Because cooperated the mailing address based on serial port PPP already to accept by each kind of ISP. Moreover the VxWorks system also supports the PPP agreement, therefore, under VxWorks through the Modem establishment and the ISP physical connection, then completes equipment’s PPP data link establishment again, may realize the remote control through Internet.
4 concluding remark
How does the image gathering system’s key is carry on the interim, the compression, the transmission and processing to the large capacity information. This system may solve these n difficult problem well. Uses the DSP storage space fully in the pictorial information interim aspect the extendibility, but guarantee system interim information content enough big; But the data compression is the matter which DSP most excels to do, DSP may in a short time complete the massive data compression work; The PCI main line’s introduction may guarantee that the information carries on the speedy transmission under the enough band width. But uses the embedded VxWorks operating system to enable the system to have the good flexibility and the compatibility, simultaneously also greatly reduced the system cost.
