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university:tools:pluto:controlling_the_transceiver_and_transferring_data [28 Apr 2017 11:29]
Michael Hennerich
university:tools:pluto:controlling_the_transceiver_and_transferring_data [28 Apr 2017 16:06]
Michael Hennerich [Receiving data]
Line 17: Line 17:
   * [[https://​www.youtube.com/​watch?​v=CS9NuRBzN5Y|libiio API introduction presentation video]]   * [[https://​www.youtube.com/​watch?​v=CS9NuRBzN5Y|libiio API introduction presentation video]]
  
 +===== Controlling the transceiver =====
 +
 +The code snippet below is a minimalistic example without error checking.
 +It shows how to control the AD936x transceiver via a remote connection.
 +
 +  - Create IIO IP Network context. Instead of ip:​xxx.xxx.xxx.xxx it'll also accept usb:XX.XX.X
 +  - Get the AD936x PHY device structure
 +  - Set the TX LO frequency (see [[resources:​tools-software:​linux-drivers:​iio-transceiver:​ad9361|AD9361 device driver documentation]]) ​
 +  - Set RX baseband rate
 + 
 +\\
 +<code c>
 +int main (int argc, char **argv)
 +{
 + struct iio_context *ctx;
 + struct iio_device *phy;
 +
 + ctx = iio_create_context_from_uri("​ip:​192.168.2.1"​);​
 +
 + phy = iio_context_find_device(ctx,​ "​ad9361-phy"​);​
 +
 + iio_channel_attr_write_longlong(
 + iio_device_find_channel(phy,​ "​altvoltage0",​ true),
 + "​frequency",​
 + 2400000000);​ /* RX LO frequency 2.4GHz */
 +
 + iio_channel_attr_write_longlong(
 + iio_device_find_channel(phy,​ "​voltage0",​ false),
 + "​sampling_frequency",​
 + 50000000);​ /* RX baseband rate 50 MSPS */
 +
 + receive(ctx);​
 +
 + iio_context_destroy(ctx);​
 +
 + return 0;
 +
 +</​code>​
 +
 +===== Receiving data =====
 +
 +  - Get the RX capture device structure
 +  - Get the IQ input channels
 +  - Enable I and Q channel
 +  - Create the RX buffer
 +  - Fill the buffer ​
 +  - Process samples
 +
 +\\
 +
 +<code c>
 +int receive(struct iio_context *ctx)
 +{
 + struct iio_device *dev;
 + struct iio_channel *rx0_i, *rx0_q;
 + struct iio_buffer *rxbuf;
 +
 + dev = iio_context_find_device(ctx,​ "​cf-ad9361-lpc"​);​
 +
 + rx0_i = iio_device_find_channel(dev,​ "​voltage0",​ 0);
 + rx0_q = iio_device_find_channel(dev,​ "​voltage1",​ 0);
 +
 + iio_channel_enable(rx0_i);​
 + iio_channel_enable(rx0_q);​
 +
 + rxbuf = iio_device_create_buffer(dev,​ 4096, false);
 + if (!rxbuf) {
 + perror("​Could not create RX buffer"​);​
 + shutdown();​
 + }
 +
 + while (true) {
 + void *p_dat, *p_end, *t_dat;
 + ptrdiff_t p_inc;
 +
 + iio_buffer_refill(rxbuf);​
 +
 + p_inc = iio_buffer_step(rxbuf);​
 + p_end = iio_buffer_end(rxbuf);​
 +
 + for (p_dat = iio_buffer_first(rxbuf,​ rx0_i); p_dat < p_end; p_dat += p_inc, t_dat += p_inc) {
 + const int16_t i = ((int16_t*)p_dat)[0];​ // Real (I)
 + const int16_t q = ((int16_t*)p_dat)[1];​ // Imag (Q)
 +
 + /* Process here */
 +
 + }
 + }
 +
 + iio_buffer_destroy(rxbuf);​
 +
 +}
 +</​code>​
  
university/tools/pluto/controlling_the_transceiver_and_transferring_data.txt · Last modified: 18 Dec 2020 17:55 by Rob Riggs