dddvb/docs/modulator_mci_api

MCI API for modulators:

Notes:

The API is not meant to be used directly but via the app/modconfig command.
Example config files for DVB-T and DVB-C are in apps/modulator.conf and
apps/modulator-c.conf, respectively.

stream - refers to one modulator slot which take a TS and modulates it
         e.g. the FSM16 has 16 streams

channel - an actual frequency the stream is sent on
          the FSM cards in default config have 96 channels at 114 MHz + X * 8 MHz (X=0-95)



MCI commands can be sent to modulators with the IOCTL_DDB_MCI_CMD:

#define IOCTL_DDB_MCI_CMD    _IOWR(DDB_MAGIC, 0x0c, struct ddb_mci_msg)

with

struct ddb_mci_msg {
	__u32 link;
	struct mci_command cmd;
	struct mci_result res;
};

link is always 0 for modulators.

mci_command with the entries relevant to modulators looks like this:

struct mci_command {
	union {
		u32 command_word;
		struct {
			u8 command;
			u8 tuner;
			u8 demod;
			u8 output;
		};
		struct {
			u8 mod_command;
			u8 mod_channel;
			u8 mod_stream;
			u8 mod_rsvd1;
		};
	};
	union {
	        ...
		struct mod_setup_channels mod_setup_channels[4];
		struct mod_setup_stream mod_setup_stream;
		struct mod_setup_output mod_setup_output;
		...
		};		    
};

mci_result like this:

struct mci_result {
	union {
		u32 status_word;
		struct {
			u8  status;
			u8  mode;
			u16 time;
		};
	};
	...

};



mci_command.command can be one of:

#define MOD_SETUP_CHANNELS        (0x60)
#define MOD_SETUP_OUTPUT          (0x61)
#define MOD_SETUP_STREAM          (0x62)

which use the following corresponding structs in mci_command:



MOD_SETUP_CHANNELS:

mod_command = MOD_SETUP_CHANNELS
mod_channel and mod_stream are not used


struct mod_setup_channels {
	u8   flags;
	u8   standard;
	u8   num_channels;
	u8   rsvd;
	u32  frequency;
	u32  offset;            /* used only when Standard == 0 */
	u32  bandwidth;         /* used only when Standard == 0 */
};

You can set up to 4 regions of channels.

flags:
#define MOD_SETUP_FLAG_FIRST      (0x01)
#define MOD_SETUP_FLAG_LAST       (0x02)
#define MOD_SETUP_FLAG_VALID      (0x80)

Set first/last if this is the first and/or last region you define.
Set valid if you actually want to set it.


standard:

see MOD_STANDARD_* defines in ddbridge-mci.h
for FSM cards only MOD_STANDARD_DVBC_6/7/8 are relevant


num_channels:

number of channels in this channel region


frequency:

start frquency of this region
frequency offset between channels depends on standard (e.g. 8MHz for DVBC_8)


offset/bandwidth: set offsets between channels and bandwidth by hand (not for FSM cards)


NOTE: After changing the channel setup you have to set the streams you want to use at least once
      before you use them. Otherwise, they will not have the new channel frequency.



MOD_SETUP_OUTPUT:

set mod_command to MOD_SETUP_OUTPUT
mod_channel and mod_stream are not used


struct mod_setup_output {
	u8   connector;         /* 0 = OFF, 1 = F, 2 = SMA */
	u8   num_channels;      /* max active channels, determines max power for each channel. */
	u8   unit;              /* 0 = dBµV, 1 = dBm, */
	u8   rsvd;
	s16  channel_power;
};

connector:         use the F- or SMA-connector (the FSM cards only has F)

num_channels:      how many channels will have actually have a stream using it (has to be less or equal to card stream capability)
                   This influences internal multipliers. Setting it lower improves signal quality.


unit:              determines unit of channel_power (0 = dBµV, 1 = dBm)

channel_power:     set channel power of output to X dBµV or dBm.



MOD_SETUP_STREAM:


mod_command =   MOD_SETUP_STREAM
mod_stream  =   stream you want to configure
mod_channel =   channel the stream is to be sent on


struct mod_setup_stream {
	u8   standard;
	u8   stream_format;
	u8   rsvd1[2];
	u32  symbol_rate;        /* only used when Standard doesn't define a fixed symbol rate */
	union {
		struct mod_ofdm_parameter ofdm;
		struct mod_qam_parameter qam;
	};
};