Brian Padalino wrote: > On 7/16/07, George Nychis <[EMAIL PROTECTED]> wrote: >> So I think what Leo is getting at is how to actually perform the read or >> the write to a register for the C/S packets. For instance we have the >> read/write register commands where the application says read from >> register X or write this data to it. >> >> This would pertain to OP_WRITE_REG, OP_WRITE_REG_MASKED, OP_READ_REG, >> and OP_READ_REG_REPLY: >> http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/doc/inband-signaling-usb >> >> >> I'm assuming what Leo is wondering, is when I pass him register 3 for >> instance, how he can actually perform the read or write. > > Major surgery. Disconnect the I2C pins between the FX2 and the FPGA > logic (float the pins coming in, and ground the pin going out?). Then > every register has to be put into a register file which the C/S state > machine has the ability to read/write, and create input ports for each > of the modules which have registers associated with them.
FPGA registers are not set using I2C, they are set with SPI. There is already a mechanism for reading back values over SPI, but it is only set up to read back 8 values now, mostly for reading io pins and rssi levels, but not every register. See serial_io.v and setting_reg.v > You may be able to use a spare pin connected to the FX2 to perform > some weird loopback thing where the host sends to FX2 which then sends > to the FPGA. The FPGA notices it must write a register, so it sends a > special packet back to the FX2 which the FX2 parses after it reads (no > DMA here) and then performs the I2C write, but that is a big old mess > too. No hardware modifications necessary . Matt _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
