usb_serial_port driver

Notes on INF files Introduction INF files are in general not a feature in Windows CE, however to configure a USB device to load the appropriate device driver corresponding to a particular VID and PID requires access to a registry editor which (unlike windows) is not always available on a windows CE platform. Using INF files to configure the driver to load properly and initialise some device settings helps users from a windows background to use the drivers without the need for a registry editor or a complete recompile of the driver with each new VID and PID. On loading the driver parses the INF file (which must be located in the Windows directory) to extract settings such as VID/PID and Latency timer. It then populates the registry with the appropriate values to enable all future removal and insertion of the device to load the FTDI driver. Please note: INF files are for INSTALLATION ONLY. After a particular device has been installed the inf file becomes redundant and changes to the inf file will not affect the device. Altering the INF file The following sections guide you through the steps to alter the FTDIPORT INF file. Please do not alter the name of this file as the driver will not recognise any other file name. WARNING: YOU MUST NOT CHANGE THE GENERAL FORMAT OF THE INF FILE - DOING THIS COULD CAUSE YOUR INSTALLATION TO HALT THE DEVICE AND THEREFORE REQUIRE A REBOOT. BEFORE PERFORMING THE FOLLOWING PROCEDURE IT IS RECOMMENDED YOU BACK UP ALL ESSENTIAL DATA. If you have any doubt on how to alter the INF file then contact support who can help with this process. Alternative VID/PID By default the VCP driver for windows CE (ftdi_ser.dll) will work with devices of VID and PID 0x0403 and 0x6001. Therefore if you do not copy the INF file to the Windows directory the driver will create registry settings for a USB device with VID and PID of 0x0403 and 0x6001. The INF files provided in this distribution package correspond to a VID and PID of 0x0403 and 0x6001/0x6010. If you have a device with an alternative VID and PID (use USBView on a desktop Windows PC to find out device VID and PID) you will need to edit the INF file to correspond to your device. The INF file format is a cut down version of the Windows equivalent. On loading (after you type in the driver name in the install driver dialog box) the driver will read the INF file (if it is present in the \Windows\ directory) and use the settings you provide. The section [FtdiHw] must be altered to correspond to your device VID and PID (you can obtain this using USBView on a desktop PC). For example for a device with VID 0x1234 and PID 0x4321: Original (0x0403/0x6001) INF entry [FtdiHw] %VID_0403&PID_6001.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_0403&PID_6001 New entry with a VID of 0x1234 and PID of 0x4321 [FtdiHw] %VID_1234&PID_4321.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_1234&PID_4321 Multiple VIDs and PIDs The INF file now supports multiple VID and PIDs - if you want to install 2 devices with different VIDs and PIDs you can have the following entry in the INF file: [FtdiHw] %VID_0403&PID_6001.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_0403&PID_6001 %VID_0403&PID_6010.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_0403&PID_6010 %VID_0403&PID_6011.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_0403&PID_6011 %VID_0403&PID_6012.DeviceDesc%=FtdiPort232,FTDIBUS\COMPORT&VID_0403&PID_6012 Additional INF Settings Additional settings are under the [FtdiPort232.NT.HW.AddReg] section of the INF file. All settings are added to the registry and take effect when the port is opened. LatencyTimer This sets the latency on an open (CreateFile) to a device - 1..255 HKR,,"LatencyTimer",0x00010001,25 - this will set the latency timer to 25 InitialIndex This is the initial index that will be used for this COM device. Currently the driver will assign COM ports 0 to 9 but if you require the COM port to start at 2 you could have the following setting in the INF file: HKR,,"InitialIndex",0x00010001,2 ConfigDataFlags Various settings for control lines HKR,,"ConfigDataFlags",0x00010001,33 ConfigDataFlags: bit 0: Ignore all set/clear DTR requests bit 1: Ignore all set/clear RTS requests bit 2: DTR initial state high (on open device) bit 3: RTS initial state high (on open device) bit 4: Ignore set DTR low on close device bit 5: Ignore set RTS low on close device So for example if you want all requests to DTR set or clear to be ignored and the initial state of DTR on open to be high use a ConfigDataFlags value of 5 decimal. ConfigData Aliasing of baud rate can be used to set a particular baud rate not supported by a legacy application. You in effect replace a standard baud rate for the one you require so the application calls set baud rate for say 9600 but your alias table has set this to 10000 therefore your com port will behave at 10000 baud. For more info please see app note "Configuring FT232BM Baud Rates" Use the following setting in the INF file to allow for aliasing of baud rates. HKR,,"ConfigData",1,01,00,3F,3F,10,27,88,13,C4,09,E2,04,71,02,38,41,9c,80,4E,C0,34,00,1A,00,0D,00,06,40,03,80,00,00,d0,80 Persistant unplug/replug. A feature to allow the COM port to still be available on an unplug/replug or suspend resume has been added. To enable this feature you must set bit 2 of the second byte of the ConfigData flags as follows: HKR,,"ConfigData",1,01,04,00,00,10,27,88,13,C4,09,E2,04,71,02,38,41,9c,80,4E,C0,34,00,1A,00,0D,00,06,40,03,80,00,00,d0,80 PLEASE NOTE in addition to the above setting you must have unique serial numbers programmed into the devices. This is required to determine which data to attach to which device on an unplug/replug. Support for CF USB Host A registry setting may be required to support CF host cards (for example the Ratoc REX-CFU1) the following registry setting should be used in this case HKR,,"ConfigData",1,01,02,00,00,10,27,88,13,C4,09,E2,04,71,02,38,41,9c,80,4E,C0,34,00,1A,00,0D,00,06,40,03,80,00,00,d0,80 (bit 1 of the second byte of the configuration flag data). In/Out Transfer Sizes These 2 settings adjust the bulk transfer size. If you are having problems getting the driver to work (such as unable to read from the port) - try setting the InTransfer size to 64 and working upwards in multiples of 64 to find a suitable value. HKR,,"InTransferSize",0x00010001,64 HKR,,"OutTransferSize",0x00010001,4096 BulPriority/Ex HKR,,"BulkPriority",0x00010001,2 - sets the priority of the reading thread of the driver Valid range 0(High priority) to 7(Low priority). Setting this value may cause your hardware to stop functioning therefore take care when setting these values and backup any data you may need. This setting uses the legacy SetThreadPriority function. HKR,,"BulkPriorityEx",0x00010001,251 - sets the priority of the reading thread of the driver Valid range 0(High priority) to 255(Low priority). Setting this value may cause your hardware to stop functioning therefore take care when setting these values and backup any data you may need. This setting uses the current CeSetThreadPriority function. Modem Emulation As per application note AN232B-09 with the exception of using the decimal value instead of hexadecimal value for example HKR,,"EmulationMode",0x00010001,8360 will switch on DTR, DCD, RI and DSR emulation on. This is required to be placed in the \Drivers\USB\FTDI_DEVICE_XXXX\YYYYYYYY where YYYYYYYY is the device serial number or in the \Drivers\USB\FTDI_DEVICE_XXXX if the device has no serial number. Active Sync Monitoring Requests have been made to call the CeEventHasOccurred when certain modem lines change within the device. This requires a separate thread of execution when the device is unopened. The following registry setting is required to turn on this functionality HKR,,"ActiveSyncSetting",0x00010001,256128 The value cor