From 6d58b692e4d26f662e6b2317e9c65043d398f00e Mon Sep 17 00:00:00 2001 From: Martin Braun Date: Wed, 9 Mar 2022 10:16:01 +0100 Subject: docs: stream_args: Clarify usage of stream_args_t::channels This vector is no longer used with RFNoC devices. We remove references to X300 from the example, and instead use B210 as an example. --- host/include/uhd/stream.hpp | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) (limited to 'host/include') diff --git a/host/include/uhd/stream.hpp b/host/include/uhd/stream.hpp index 97cfc1ac5..87a5c0ace 100644 --- a/host/include/uhd/stream.hpp +++ b/host/include/uhd/stream.hpp @@ -128,24 +128,32 @@ struct UHD_API stream_args_t */ device_addr_t args; - /*! - * The channels is a list of channel numbers. - * Leave this blank to default to channel 0 (single-channel application). - * Set channels for a multi-channel application. - * Channel mapping depends on the front-end selection (see also \ref config_subdev). + /*! List of channel numbers (only used by non-RFNoC devices) + * + * Note: For RFNoC devices, this value is not used. To create a streamer + * with multiple channels, the uhd::rfnoc::rfnoc_graph::create_tx_streamer() + * and uhd::rfnoc::rfnoc_graph::create_rx_streamer() API calls have a + * \p num_ports argument. * - * A very simple example is an X300 with two daughterboards and a subdev spec - * of `A:0 B:0`. This means the device has two channels available. + * For non-RFNoC devices (i.e., USRP1, B100, B200, N200), this argument + * defines how streamer channels map to the front-end selection (see also + * \ref config_subdev). * - * Setting `stream_args.channels = (0, 1)` therefore configures MIMO streaming - * from both channels. By switching the channel indexes, `stream_args.channels = (1, - * 0)`, the channels are switched and the first channel of the USRP is mapped to the - * second channel in the application. + * A very simple example is a B210 with a subdev spec of `A:A A:B`. This + * means the device has two channels available. * - * If only a single channel is used for streaming, `stream_args.channels = (1,)` would - * only select a single channel (in this case, the second one). When streaming - * a single channel from the B-side radio of a USRP, this is a more versatile solution - * than setting the subdev globally to "B:0". + * Setting `stream_args.channels = {0, 1}` therefore configures MIMO + * streaming from both channels. By switching the channel indexes, + * `stream_args.channels = {1, 0}`, the channels are switched and the first + * channel of the USRP is mapped to the second channel in the application. + * + * If only a single channel is used for streaming, e.g., + * `stream_args.channels = {1}` would only select a single channel (in this + * case, the second one). When streaming a single channel from the B-side + * radio of a USRP, this is a more versatile solution than setting the + * subdev spec globally to "A:B". + * + * Leave this blank to default to channel 0 (single-channel application). */ std::vector channels; }; -- cgit v1.2.3