Hi, Stefan Schaal wrote: > Hi everybody, > > we have an NI6259 board working xenomai 2.5, using the analogy APIs. > Read/write to analog channels is quite straightforward and can be > inferred from the cmd_read and cmd_write source code. Now I would also > like to use the digital I/O of this board (e.g., the 32 digital I/O > lines). In Comedi, there are functions to set the DIO lines to > input/output mode (comedi_dio_config), and then functions to read/write, > like comedi_dio_read and comedi_dio_write. Does xenomai/analogy already > have similar functionality?
Many thanks for this question, it is an issue I have been keeping on postponing the resolution. Currently, the functions are not implemented but it could be quickly done. Here is my understanding of the Comedi DIO features; please, correct me if I am wrong. In Comedi, here is the list of functions related with DIO: - comedi_dio_read (insn_read or deprecated insn trigger) - comedi_dio_write (insn_write or deprecated insn trigger) - comedi_dio_config (insn_config or deprecated insn trigger) - comedi_dio_get_config (insn_config or deprecated trigger) - comedi_dio_bitfield (insn_bits or comedi_dio_read/write) - comedi_dio_bitfield2 (insn_bits or comedi_dio_read/write) The instruction insn_bits is a combination of a read operation and a write operation (that is why, the function comedi_dio_bitfield* call comedi_dio_read and comedi_dio_write if the driver does not provide an insn-bits handler). I had a look at many Comedi drivers and most of them register the handler "insn_bits" for the DIO subdevice. The instructions insn_read and insn_write are not oftenly used in DIO contexts. comedi_dio_bitfield() uses the insn_bits instruction. However, it only works with DIO subdevice limited to 32 channels; that was why comedi_dio_bitfield2() was introduced, this latter function contains one more argument so as to shift the bits. Consequently, we may need a more limited set of functions: - a4l_sync_dio(dsc, idx_subd, mask, buf) - a4l_sizeof_subd(dsc, idx_subd) - a4l_config_subd(dsc, idx_subd, idx_chan, cfg_type, *val) a4l_sync_dio() could work with any DIO subdevice (more or less than 32 channels). The last argument would be a pointer to a buffer which size should be defined thanks to a4l_sizeof_subd() (8, 16, 32, 64 or more bits). a4l_config_subd() could be used to configure the polarity of the DIO channels. The argument cfg_type could be set to DIO_INPUT, DIO_OUTPUT, DIO_QUERY. And, we could even imagine that this function would not be limited to DIO subdevice; so, the argument cfg_type could accept more values (SERIAL_CLOCK, BIDIRECTIONAL_DATA, SET_CLOCK_SRC, GET_CLOCK_SRC, etc.) How do you see this approach ? Do you (or anyone else) have a better solution in mind ? Best regards, > Thanks a lot, > > -Stefan > _______________________________________________ > Xenomai-core mailing list > Xenomai-core@gna.org > https://mail.gna.org/listinfo/xenomai-core > Alexis. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
