《ARM嵌入式系统软件开发实例》教学资源（讲稿）第十讲 PDIUSBD12 固件编程指南.pdf_大学文库

Interconnectivity Page 3 of 22 Firmware Programming Guide for PDIUSBD12 _______________________________________________________________________________________________ Philips Semiconductors - Asia Product Innovation Centre Visit http://www.flexiusb.com Table of Contents 1 INTRODUCTION........................................................................................................................................... 4 2 ARCHITECTURE.......................................................................................................................................... 5 2.1 FIRMWARE STRUCTURE ............................................................................................................................... 5 2.1.1 Hardware Abstraction Layer - EPPHAL.C ........................................................................................... 5 2.1.2 PDIUSBD12 Command Interface - D12CI.C........................................................................................ 5 2.1.3 Interrupt Service Routine - ISR.C ......................................................................................................... 5 2.1.4 Main Loop - MAINLOOP.C ................................................................................................................. 6 2.1.5 Protocol Layer - CHAP_9.C, PROTODMA.C....................................................................................... 6 2.2 PORTING THE FIRMWARE TO OTHER CPU PLATFORM ................................................................................... 6 2.3 USING THE FIRMWARE IN POLLING MODE .................................................................................................... 6 3 HARDWARE ABSTRACTION LAYER ....................................................................................................... 7 4 PDIUSBD12 COMMAND INTERFACE........................................................................................................ 7 5 INTERRUPT SERVICE ROUTINE .............................................................................................................. 8 5.1 BUS RESET AND SUSPEND CHANGE.............................................................................................................. 9 5.2 CONTROL ENDPOINT HANDLER.................................................................................................................. 10 5.3 GENERIC ENDPOINT HANDLER................................................................................................................... 13 5.4 MAIN ENDPOINT HANDLER........................................................................................................................ 13 5.5 EOT HANDLER ......................................................................................................................................... 13 6 MAIN LOOP................................................................................................................................................. 14 7 CHAPTER 9 PROTOCOL........................................................................................................................... 15 7.1 CLEAR FEATURE REQUEST ........................................................................................................................ 15 7.2 GET STATUS REQUEST............................................................................................................................... 16 7.3 SET ADDRESS REQUEST............................................................................................................................. 16 7.4 GET CONFIG REQUEST............................................................................................................................... 17 7.5 GET DESCRIPTOR REQUEST ....................................................................................................................... 17 7.6 SET CONFIG REQUEST ............................................................................................................................... 18 7.7 GET/SET INTERFACE REQUEST................................................................................................................... 18 7.8 SET FEATURE REQUEST ............................................................................................................................. 19 8 DMA SUPPORT............................................................................................................................................ 20 8.1 INTRODUCTION TO PROTOCOL BASED DMA OPERATION ............................................................................ 20 8.2 DEVICE'S DMA STATES............................................................................................................................. 20 8.3 DMA CONFIGURATION REGISTER.............................................................................................................. 21 8.4 SETUP DMA REQUEST .............................................................................................................................. 21 8.5 HOST SIDE PROGRAMMING CONSIDERATIONS............................................................................................. 22

Interconnectivity Page 4 of 22 Firmware Programming guide for PDIUSBD12 1 Introduction PDIUSBD12 is a high-speed USB interface device with parallel bus and local DMA transfer capability. The objective of the recommended firmware design is to enable PDIUSBD 12 to achieve the fastest transfer rate over USB Peripheral devices such as the printer, scanner, external mass storage, and digital camera can use PDIUSBD12 in transferring data over USB. The CPUs in these devices are very busy in handling many tasks like device control and data and image processing. The firmware of PDIUSBD 12 is designed to be fully interrupt-driven While CPU is doing its foreground task, the USB transfer is being handled in the background. This assures best transfer rate and better software structure and also simplifies programming and debugging The data exchange between the background ISR (Interrupt Service Routine) and the foreground Main Loop is achieved by event flags and data buffers. For example, the PDIUSBD12 Main bulk out endpoint can use a circular data buffer. When PDIUSBD12 receives a data packet from USB, an interrupt request is generated to the CPU and the CPU will service ISR immediately. Inside the ISR, the firmware moves the data packet to the ircular buffer from pdiusbd12 's internal buffer and then clears the pdiusbd i2's internal buffer to enable PDIUSBD12 to receive new packet. The CPU can continue its current foreground task until completion, e.g printing current page. Then it returns to the main loop, checks the circular buffers for new data, and starts another foreground task RXRP, Read Pointer maintained by main loop Main loop in foreground ISR in background Circular data buffer RXWP, Write Pointer maintained by ISr With this structure, the Main Loop does not care whether the data source is from USB, serial port, or parallel port. The Main Loop only checks the circular buffer for new data to be processed. This concept is very important. Thus, the Main Loop program can target on data processing and the ISr can do the job of data transfer at the fastest speed possible Similarly, the control endpoint uses the same concept in data packet handling. The ISR receives and stores control transfers in data buffers and sets the corresponding flag registers. The main loop will dispatch the request to protocol handling routines. Since all the standard device, class, and vendor requests are processed in protocol handling routines, ISR can maintain its efficiency. Also, when new request is added, only modification at the protocol level is needed llips Semiconductors-Asia Product Innovation Centre Visithttp://www.fler

Interconnectivity Page 4 of 22 Firmware Programming Guide for PDIUSBD12 Philips Semiconductors - Asia Product Innovation Centre Visit http://www.flexiusb.com 1. Introduction PDIUSBD12 is a high-speed USB interface device with parallel bus and local DMA transfer capability. The objective of the recommended firmware design is to enable PDIUSBD12 to achieve the fastest transfer rate over USB. Peripheral devices such as the printer, scanner, external mass storage, and digital camera can use PDIUSBD12 in transferring data over USB. The CPUs in these devices are very busy in handling many tasks like device control and data and image processing. The firmware of PDIUSBD12 is designed to be fully interrupt-driven. While CPU is doing its foreground task, the USB transfer is being handled in the background. This assures best transfer rate and better software structure and also simplifies programming and debugging. The data exchange between the background ISR (Interrupt Service Routine) and the foreground Main Loop is achieved by event flags and data buffers. For example, the PDIUSBD12 Main bulk out endpoint can use a circular data buffer. When PDIUSBD12 receives a data packet from USB, an interrupt request is generated to the CPU and the CPU will service ISR immediately. Inside the ISR, the firmware moves the data packet to the circular buffer from PDIUSBD12's internal buffer and then clears the PDIUSBD12's internal buffer to enable PDIUSBD12 to receive new packet. The CPU can continue its current foreground task until completion, e.g. printing current page. Then it returns to the main loop, checks the circular buffers for new data, and starts another foreground task. With this structure, the Main Loop does not care whether the data source is from USB, serial port, or parallel port. The Main Loop only checks the circular buffer for new data to be processed. This concept is very important. Thus, the Main Loop program can target on data processing and the ISR can do the job of data transfer at the fastest speed possible. Similarly, the control endpoint uses the same concept in data packet handling. The ISR receives and stores control transfers in data buffers and sets the corresponding flag registers. The main loop will dispatch the request to protocol handling routines. Since all the standard device, class, and vendor requests are processed in protocol handling routines, ISR can maintain its efficiency. Also, when new request is added, only modification at the protocol level is needed. ISR in background Main loop in foreground RXWP, Write Pointer maintained by ISR RXRP, Read Pointer maintained by main loop Circular data buffer

Interconnectivity Page 6 of 22 Firmware Programming Guide for PDIUSBD12 Philips Semiconductors - Asia Product Innovation Centre Visit http://www.flexiusb.com 2.1.4 Main Loop - MAINLOOP.C The Main Loop checks the event flags and passes to appropriate subroutine for further processing. It also contains the code for human interface, such as LED and key scan. 2.1.5 Protocol Layer - CHAP_9.C, PROTODMA.C The Protocol layer handles standard USB device requests, as well as specific vendor requests such as DMA and TWAIN. 2.2 Porting the Firmware to Other CPU Platform Below table shows the modifications on building blocks need to be done. There are two levels of porting. First is Chapter 9 only, which is only make the firmware to pass enumeration by supporting standard USB requests. The second level is full product development, this will involve product specific firmware code. File Name Chapter 9 Only Product Level EPPHAL.C Port to hardware specific. Port to hardware specific. D12CI.C No change. No change. CHAP_9.C No change. Product specific USB descriptors. PROTODMA.C No change. Add vendor request supports if necessary. ISR.C No change. Add product specific processing on Generic and Main endpoints. MAINLOOP.C Depends on the CPU and system, ports, timer and interrupt initialization need to be rewritten. Add product specific Main Loop processing. There are CPU and compiler dependent pre-definitions in MAINLOOP.H: #ifdef __C51__ #define SWAP(x) ((((x) & 0xFF) > 8) & 0xFF)) #else #define SWAP(x) (x) #define code #define idata #endif Note the "SWAP" is necessary for micro-controllers, which are big endian format, such as 8031. The "code" and "idata" is only necessary when using 8031 and Keil C compiler. 2.3 Using the Firmware in Polling Mode It's very easy to use the firmware in polling mode. Inside the Main Loop, add following code: if(interrupt_pin_low) fn_usb_isr(); Normally ISR is initiated by hardware. In polling mode, the Main Loop detects interrupt pin's state, and invokes ISR if necessary

Interconnectivity Page 7 of 22 Firmware Programming Guide for PDIUSBD12 Philips Semiconductors - Asia Product Innovation Centre Visit http://www.flexiusb.com 3. Hardware Abstraction Layer This layer contains the lowest layer functions that need to be changed on different CPU platforms. void outportb(unsigned char port, unsigned char val); void inportb(unsigned char port); void dma_start(PIO_REQUEST pio) All I/O access to PDIUSBD12 should be implemented by the first two functions above (outportb and inportb). As for the last function, it is meant for implementing the "EPP DMA" function. The latter is for setting the EPP page address and CPLD counter. This type of implementation can allow the system to be platform independent, which means that the application's architecture can be used for platform other than 8051 or the PC. For USB_EPP evaluation board, the dma_start() functions calls the 2 function below, which are not necessary to be implemented in target application. void eppAwrite(unsigned char A_data); void program_cpld(unsigned short uSize, unsigned char bCommand); 4. PDIUSBD12 Command Interface The following functions are defined as PDIUSBD12 command interface to simplify device programming. They are simple implementations of the PDIUSBD12 command set, which is defined in the data sheet. void D12_SetAddressEnable(unsigned char bAddress, unsigned char bEnable); void D12_SetEndpointEnable(unsigned char bEnable); void D12_SetMode(unsigned char bConfig, unsigned char bClkDiv); void D12_SetDMA(unsigned char bMode); unsigned short D12_ReadInterruptRegister(void); unsigned char D12_SelectEndpoint(unsigned char bEndp); unsigned char D12_ReadLastTransactionStatus(unsigned char bEndp); void D12_SetEndpointStatus(unsigned char bEndp, unsigned char bStalled); void D12_SendResume(void); unsigned short D12_ReadCurrentFrameNumber(void); unsigned char D12_ReadEndpoint(unsigned char endp, unsigned char * buf, unsigned char len); unsigned char D12_WriteEndpoint(unsigned char endp, unsigned char * buf, unsigned char len); void D12_AcknowledgeEndpoint(unsigned char endp);