Abstract integration peripheral device’s increase, software application complexity further increase, causes the work load which the development peripheral device driver needs to increase greatly. TI Corporation proposed the kind of/micro actuation model driver structure. The practice result indicated that after using class/the micro actuation model carries on the driver design, the application software may the multiplying major part similar equipment’s driver, thus raised the driver development efficiency enormously.
Key word DM642 I/O equipment actuation class/micro actuation model DSP/BlOS real-time operating system
In recent years, the DSP operational capability’s unceasing enhancement, enabled it to obtain the widespread application in the electronic installation aspect. DSP/BIOS is a real-time operating system which TI Corporation promotes, with TI CCS (Code Composer Studio) integrates in together. May simplify the DSP application procedure greatly with DSP/BIOS the development and the debugging, with auxiliary equipment’s I/O connection is in the DSP application development the essential important part. TI Corporation was C64x the series DSP exploiter has provided a type/micro actuation model (class/mini drivermodel). Through to the auxiliary equipment design driver, provides the unification for the high-level application procedure the connection to operate the first floor hardware. So long as the foot follows this driver interface standard development the high-level application procedure, may in have in the same connection different hardware platform to move, thus causes the DSP software system and the hardware system separates, enhanced software’s reusability, the maintainability and the probability, reduced the overall driver development cycle.
1 DSP peripheral device actuation development model
TI Corporation to develop DSP the peripheral device driver to define the standard equipment to actuate the model, and actuated the equipment to divide into a kind of actuation and the micro actuation, namely relied on the hardware level and does not rely on the hardware level. Between two uses the general connection to carry on the data communication, and provided a series of API connection, the user application procedure through transferred API to visit the corresponding external instrumentation. The peripheral device actuation development model’s establishment, enhanced the peripheral device driver reusability and the modular degree, simplified the driver development. Peripheral device development model as shown in Figure 1.
①Kind of actuation (class driver). The kind of driver uses for the application procedure to provide the connection. This subprograms with the hardware equipment which uses have nothing to do with, the major function including the service facilities buffer, provides the API connection supply to transfer upwardly with the procedure, provides the adaptive level to be connected downward with the micro actuation level, realizes the API connection function to the micro actuation level procedure mapping.
②Micro actuation (mini driver). The micro driver is related with the external hardware equipment, therefore designs the micro driver is the peripheral device actuation development key point. The micro driver with the kind of driver’s connection form is fixed, but the micro driver must different need to make the corresponding modification to the first floor hardware’s operation according to the hardware platform. The micro actuation the transfer order which sends out through the receive class actuation level decided that what operation carries on to the first floor hardware.
A kind of actuation transfers the micro actuation control hardware equipment through the standard micro actuation connection. To date, TI has altogether defined 3 kind of actuations:①Class input output module (SIO), provides an independent I/O mechanism for each DSP/BIOS thread, carries out the point-to-point data transfer, supports the dynamic foundation, through the DIO adaptive module and IOM connection;②Pipeline administration module (PIP), provides management asynchronous I/O the data pipeline, each pipeline object has the similar size buffer, the PIP module carries on the data transmission together through the buffer, through the PIO adaptive module and IOM correspondence;③General input output module (GIO), based on class input/output pattern’s synchronized I/O, suits the great current capacity data the transmission, more suitable filing system. May transfer GIO directly in the user application procedure the API function, GIO does not need the extra adaptive module, may carry on directly with IOM alternately. GIO these merits cause through the GIO module to carry on the data stream transmission with the external instrumentation, the simplicity of operator, stably, therefore has used general input output module GIO in a video frequency gathering kind of actuation.
The GIO module realizes a GIO kind of actuation, uses in providing a modular the read-write application program interface to the application procedure. Through seals this part of codes, the application procedure may the application program interface which provides through GIO ask that meets transfers each kind of IOM micro actuation to reduce the whole the code size, as shown in Figure 2.
The GIO module provides the following function: Provides modular the read-write application procedure; With assigns the equipment micro actuation with the IOM connection to realize the procedure correspondence; Supports many equipment to actuate; Supports the duplex channel; Permission user disposition modulation function; The support application procedure increases the new application domain (for example video frequency). And, the function is very last important. Application program interface (API) which the GIO_submit function to increases the user who has custom-made to provide the standard channel newly (for example video). This kind of user has custom-made the type including uses in filing system’s read-write application program interface module, for example UART, DSP video frequency frame and so on application.
The traditional filing system completes between the application procedure and the document data transmission with the read-write application program interface, needs completes the duplex channel which by a GIO kind of actuation and the IOM micro actuation needs. May in a friendly way and realizes the video frequency capture and the video frequency demonstration highly effective to the GIO interface module’s expansion. This kind of expansion has satisfied (frame buffer which specially the video equipment storage space e.g. assigns) assignment, moreover renews the video frequency frame buffer through the simple application procedure transfer, provides between the video frequency actuation and the application procedure the newest video data renewal. A GIO kind of actuation has the following connection. Assigns equipment’s operator schema in the function table:
Micro actuates IOM usually to include following function: Channel binding function (md-BindDev), the channel founds function (mdCreateChan), the channel deletes function (mdDeleteChan), I/O request transmission function (mdSubitChan), channel solution binding function (mdUnBindDev) and device control function (mdControl-Chan). A kind of actuation through transfers these first floor function to complete the corresponding external instrumentation and between the application procedure data-transmission channel’s foundation, as well as the external instrumentation and the memory space’s assignment, controls between each thread the data transfer synchronization and so on. These stipulated that the good first floor function will put in the micro actuation the function to meet in oral thermometer (IOM_Fxns) the relevant position, for application procedure through adaptive module or directly by GIO kind of actuation transfer. IOM meets oral thermometer’s structure to be as follows:
Before transferring the IOM micro actuation, must register first in DSP/BIOSConfig. Strikes the choice in Device Drivers to insert an equipment right to actuate, the naming is VPlACAPTURE, and carries on each attribute (for example function table indicator, function table type and the equipment ID number and so on) the disposition, indicates the IOM-Fxns function table address and the plant parameter address, as shown in Figure 3.
2 DM642 chip video frequency driver design
The video frequency driver’s design mainly includes the micro actuation, a kind of actuation and the middle connection 3 aspect design. For the greatest degree enhances the video frequency actuation code the reusability and the versatility, in the video frequency gathering driver example, further seals the FVID kind in the GIO kind of driver foundation. Subdivides the micro actuation for the video frequency port class and assigns to arrange the decoding chip micro actuation, between the two realizes through external instrumentation control interface (EDC) to the periphery chip opens, operations and so on control and closure. As the matter stands, even if in the board card which used integrates the different video frequency to arrange the decoding chip, also only need change establishes a table of organization especially the decoding chip micro actuation. Video frequency gathering driver’s kind of/micro actuation model as shown in Figure 4.
For example, belongs to the VPORT_PortParams connection’s explanation to the VPORT port’s class explanation, but belongs to the SAA712l connection’s explanation to the specific code chip explanation. If uses in the VPORT kind the different chip, then only need make the revision to SAA712l. To the EDC connection explained that as follows (assigns to carry on to auxiliary equipment opens, closure and so on operation):
Below explains with examples to the FVID kind of actuation video frequency application program interface (video API) operation. Speaking of the application procedure, may divide into 3 stages to device driver’s operation: Foundation, processing and deletion. The foundation is establishes a data feeds/output in the application procedure with the external instrumentation between the logical channel, corresponds in FVID_create; Processing is carries on the data in the application procedure with the external instrumentation between the transmission, and carries on the corresponding control to the peripheral device, corresponds in FVID_control and FVID_alloc; After the peripheral device use finished, deleted the channel which correspondingly established originally, corresponded in FVID_delete. The concrete transfer function is as follows:
Conclusion
This article introduced TI Corporation develops after kind of/micro actuation model and improvement, DM64z video frequency class/micro actuation model. The practice indicated that the DM642 video frequency class/micro actuation model reduced in the system between software and hardware’s coupling, enhanced the driver reusability and the probability, simplified the video frequency driver development.
