Florian Echtler <echtler <at> fs.tum.de> writes: > Hello everyone, > > I was just thinking about using an USB printer interface cable > as a cheap interface for some homebrewn hardware. However, it > would be truly convenient to be able to use all the output lines > that the standard parallel port offers: Select Printer, Autofeed, > Strobe and Init. > > I assume the Strobe signal is usually auto-generated in the > interface chip - not much of a problem. > > Are the other signals in any way accessible via USB? Any IOCTLs > in the usblp driver? I looked through the source and couldn't > find any.. I don't think that there are any signals that are directly controllable or accessible. Control is done via messages. There are a few ioctl's. The USB printer spec defines these: GET_DEVICE_ID, GET_PORT_STATUS, and SOFT_RESET. (You can get this spec. from www.usb.org) Did you look at the usblp.c source code? It defines these ioctl's: /* ioctls: */ #define LPGETSTATUS 0x060b /* same as in drivers/char/lp.c */ #define IOCNR_GET_DEVICE_ID 1 #define IOCNR_GET_PROTOCOLS 2 #define IOCNR_SET_PROTOCOL 3 #define IOCNR_HP_SET_CHANNEL 4 #define IOCNR_GET_BUS_ADDRESS 5 #define IOCNR_GET_VID_PID 6 #define IOCNR_SOFT_RESET 7 /* Get device_id string: */ #define LPIOC_GET_DEVICE_ID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_DEVICE_ID, len) /* The following ioctls were added for http://hpoj.sourceforge.net: */ /* Get two-int array: * [0]=current protocol (1=7/1/1, 2=7/1/2, 3=7/1/3), * [1]=supported protocol mask (mask&(1<<n)!=0 means 7/1/n supported): */ #define LPIOC_GET_PROTOCOLS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_PROTOCOLS, len) /* Set protocol (arg: 1=7/1/1, 2=7/1/2, 3=7/1/3): */ #define LPIOC_SET_PROTOCOL _IOC(_IOC_WRITE, 'P', IOCNR_SET_PROTOCOL, 0) /* Set channel number (HP Vendor-specific command): */ #define LPIOC_HP_SET_CHANNEL _IOC(_IOC_WRITE, 'P', IOCNR_HP_SET_CHANNEL, 0) /* Get two-int array: [0]=bus number, [1]=device address: */ #define LPIOC_GET_BUS_ADDRESS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_BUS_ADDRESS, len) /* Get two-int array: [0]=vendor ID, [1]=product ID: */ #define LPIOC_GET_VID_PID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_VID_PID, len) /* Perform class specific soft reset */ #define LPIOC_SOFT_RESET _IOC(_IOC_NONE, 'P', IOCNR_SOFT_RESET, 0); ~Randy
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