summaryrefslogtreecommitdiff
path: root/usrp/host/lib/legacy/usrp_basic.h
blob: 796a0f4940f1e1797fa1ded7928141cc211dd8a0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
/* -*- c++ -*- */
/*
 * Copyright 2003,2004 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 * 
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

/*
 * ----------------------------------------------------------------------
 * Mid level interface to the Universal Software Radio Peripheral (Rev 1)
 *
 * These classes implement the basic functionality for talking to the
 * USRP.  They try to be as independent of the signal processing code
 * in FPGA as possible.  They implement access to the low level
 * peripherals on the board, provide a common way for reading and
 * writing registers in the FPGA, and provide the high speed interface
 * to streaming data across the USB.
 *
 * It is expected that subclasses will be derived that provide
 * access to the functionality to a particular FPGA configuration.
 * ----------------------------------------------------------------------
 */

#ifndef INCLUDED_USRP_BASIC_H
#define INCLUDED_USRP_BASIC_H

#include <usrp_slots.h>
#include <string>

struct usb_dev_handle;
class  fusb_devhandle;
class  fusb_ephandle;

/*!
 * \brief base class for usrp operations
 */
class usrp_basic
{
private:
  // NOT IMPLEMENTED
  usrp_basic (const usrp_basic &rhs);			// no copy constructor
  usrp_basic &operator= (const usrp_basic &rhs);	// no assignment operator

  
protected:
  struct usb_dev_handle	*d_udh;
  int			 d_usb_data_rate;	// bytes/sec
  int			 d_bytes_per_poll;	// how often to poll for overruns
  bool			 d_verbose;

  static const int	 MAX_REGS = 128;
  unsigned int		 d_fpga_shadows[MAX_REGS];

  usrp_basic (int which_board,
	      struct usb_dev_handle *open_interface (struct usb_device *dev),
	      const std::string fpga_filename = "",
	      const std::string firmware_filename = "");

  /*!
   * \brief advise usrp_basic of usb data rate (bytes/sec)
   *
   * N.B., this doesn't tweak any hardware.  Derived classes
   * should call this to inform us of the data rate whenever it's
   * first set or if it changes.
   *
   * \param usb_data_rate	bytes/sec
   */
  void set_usb_data_rate (int usb_data_rate);
  
  /*!
   * \brief Write auxiliary digital to analog converter.
   *
   * \param slot	Which Tx or Rx slot to write.
   *    		N.B., SLOT_TX_A and SLOT_RX_A share the same AUX DAC's.
   *          		SLOT_TX_B and SLOT_RX_B share the same AUX DAC's.
   * \param which_dac	[0,3] RX slots must use only 0 and 1.  TX slots must use only 2 and 3.
   * \param value	[0,4095]
   * \returns true iff successful
   */
  bool write_aux_dac (int slot, int which_dac, int value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param slot	2-bit slot number. E.g., SLOT_TX_A
   * \param which_adc	[0,1]
   * \param value	return 12-bit value [0,4095]
   * \returns true iff successful
   */
  bool read_aux_adc (int slot, int which_adc, int *value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param slot	2-bit slot number. E.g., SLOT_TX_A
   * \param which_adc	[0,1]
   * \returns value in the range [0,4095] if successful, else READ_FAILED.
   */
  int read_aux_adc (int slot, int which_adc);

public:
  virtual ~usrp_basic ();

  /*!
   * \brief return frequency of master oscillator on USRP
   */
  long  fpga_master_clock_freq () const { return 64000000; }

  /*!
   * \returns usb data rate in bytes/sec
   */
  int usb_data_rate () const { return d_usb_data_rate; }

  void set_verbose (bool on) { d_verbose = on; }

  //! magic value used on alternate register read interfaces
  static const int READ_FAILED = -99999;

  /*!
   * \brief Write EEPROM on motherboard or any daughterboard.
   * \param i2c_addr		I2C bus address of EEPROM
   * \param eeprom_offset	byte offset in EEPROM to begin writing
   * \param buf			the data to write
   * \returns true iff sucessful
   */
  bool write_eeprom (int i2c_addr, int eeprom_offset, const std::string buf);

  /*!
   * \brief Read EEPROM on motherboard or any daughterboard.
   * \param i2c_addr		I2C bus address of EEPROM
   * \param eeprom_offset	byte offset in EEPROM to begin reading
   * \param len			number of bytes to read
   * \returns the data read if successful, else a zero length string.
   */
  std::string read_eeprom (int i2c_addr, int eeprom_offset, int len);

  /*!
   * \brief Write to I2C peripheral
   * \param i2c_addr		I2C bus address (7-bits)
   * \param buf			the data to write
   * \returns true iff successful
   * Writes are limited to a maximum of of 64 bytes.
   */
  bool write_i2c (int i2c_addr, const std::string buf);

  /*!
   * \brief Read from I2C peripheral
   * \param i2c_addr		I2C bus address (7-bits)
   * \param len			number of bytes to read
   * \returns the data read if successful, else a zero length string.
   * Reads are limited to a maximum of 64 bytes.
   */
  std::string read_i2c (int i2c_addr, int len);

  /*!
   * \brief Set ADC offset correction
   * \param which	which ADC[0,3]: 0 = RX_A I, 1 = RX_A Q...
   * \param offset	16-bit value to subtract from raw ADC input.
   */
  bool set_adc_offset (int which, int offset);

  /*!
   * \brief Set DAC offset correction
   * \param which	which DAC[0,3]: 0 = TX_A I, 1 = TX_A Q...
   * \param offset	10-bit offset value (ambiguous format:  See AD9862 datasheet).
   * \param offset_pin	1-bit value.  If 0 offset applied to -ve differential pin;
   *                                  If 1 offset applied to +ve differential pin.
   */
  bool set_dac_offset (int which, int offset, int offset_pin);

  /*!
   * \brief Control ADC input buffer
   * \param which 	which ADC[0,3]
   * \param bypass	if non-zero, bypass input buffer and connect input
   *	                directly to switched cap SHA input of RxPGA.
   */
  bool set_adc_buffer_bypass (int which, bool bypass);


  /*!
   * \brief return the usrp's serial number.
   *
   * \returns non-zero length string iff successful.
   */
  std::string serial_number();

  // ----------------------------------------------------------------
  // Low level implementation routines.
  // You probably shouldn't be using these...
  //

  bool _set_led (int which, bool on);

  /*!
   * \brief Write FPGA register.
   * \param regno	7-bit register number
   * \param value	32-bit value
   * \returns true iff successful
   */
  bool _write_fpga_reg (int regno, int value);	//< 7-bit regno, 32-bit value

  /*!
   * \brief Read FPGA register.
   * \param regno	7-bit register number
   * \param value	32-bit value
   * \returns true iff successful
   */
  bool _read_fpga_reg (int regno, int *value);	//< 7-bit regno, 32-bit value

  /*!
   * \brief Read FPGA register.
   * \param regno	7-bit register number
   * \returns register value if successful, else READ_FAILED
   */
  int  _read_fpga_reg (int regno);


  /*!
   * \brief Write FPGA register with mask.
   * \param regno	7-bit register number
   * \param value	16-bit value
   * \param mask 	16-bit value
   * \returns true if successful
   * Only use this for registers who actually implement a mask in the verilog firmware, like FR_RX_MASTER_SLAVE
   */
  bool _write_fpga_reg_masked (int regno, int value, int mask);

  /*!
   * \brief Write AD9862 register.
   * \param which_codec 0 or 1
   * \param regno	6-bit register number
   * \param value	8-bit value
   * \returns true iff successful
   */
  bool _write_9862 (int which_codec, int regno, unsigned char value);

  /*!
   * \brief Read AD9862 register.
   * \param which_codec 0 or 1
   * \param regno	6-bit register number
   * \param value	8-bit value
   * \returns true iff successful
   */
  bool _read_9862 (int which_codec, int regno, unsigned char *value) const;

  /*!
   * \brief Read AD9862 register.
   * \param which_codec 0 or 1
   * \param regno	6-bit register number
   * \returns register value if successful, else READ_FAILED
   */
  int  _read_9862 (int which_codec, int regno) const;

  /*!
   * \brief Write data to SPI bus peripheral.
   *
   * \param optional_header	0,1 or 2 bytes to write before buf.
   * \param enables		bitmask of peripherals to write. See usrp_spi_defs.h
   * \param format		transaction format.  See usrp_spi_defs.h SPI_FMT_*
   * \param buf			the data to write
   * \returns true iff successful
   * Writes are limited to a maximum of 64 bytes.
   *
   * If \p format specifies that optional_header bytes are present, they are
   * written to the peripheral immediately prior to writing \p buf.
   */
  bool _write_spi (int optional_header, int enables, int format, std::string buf);

  /*
   * \brief Read data from SPI bus peripheral.
   *
   * \param optional_header	0,1 or 2 bytes to write before buf.
   * \param enables		bitmask of peripheral to read. See usrp_spi_defs.h
   * \param format		transaction format.  See usrp_spi_defs.h SPI_FMT_*
   * \param len			number of bytes to read.  Must be in [0,64].
   * \returns the data read if sucessful, else a zero length string.
   *
   * Reads are limited to a maximum of 64 bytes.
   *
   * If \p format specifies that optional_header bytes are present, they
   * are written to the peripheral first.  Then \p len bytes are read from
   * the peripheral and returned.
   */
  std::string _read_spi (int optional_header, int enables, int format, int len);

  /*!
   * \brief Start data transfers.
   * Called in base class to derived class order.
   */
  bool start ();

  /*!
   * \brief Stop data transfers.
   * Called in base class to derived class order.
   */
  bool stop ();
};

/*!
 * \brief class for accessing the receive side of the USRP
 */
class usrp_basic_rx : public usrp_basic 
{
private:
  fusb_devhandle	*d_devhandle;
  fusb_ephandle		*d_ephandle;
  int			 d_bytes_seen;		// how many bytes we've seen
  bool			 d_first_read;
  bool			 d_rx_enable;

protected:
  int			 d_dbid[2];		// Rx daughterboard ID's

  /*!
   * \param which_board	     Which USRP board on usb (not particularly useful; use 0)
   * \param fusb_block_size  fast usb xfer block size.  Must be a multiple of 512. 
   *                         Use zero for a reasonable default.
   * \param fusb_nblocks     number of fast usb URBs to allocate.  Use zero for a reasonable default. 
   */
  usrp_basic_rx (int which_board,
		 int fusb_block_size=0,
		 int fusb_nblocks=0,
		 const std::string fpga_filename = "",
		 const std::string firmware_filename = ""
		 );  // throws if trouble

  bool set_rx_enable (bool on);
  bool rx_enable () const { return d_rx_enable; }

  bool disable_rx ();		// conditional disable, return prev state
  void restore_rx (bool on);	// conditional set

  void probe_rx_slots (bool verbose);
  int  dboard_to_slot (int dboard) { return (dboard << 1) | 1; }

public:
  ~usrp_basic_rx ();

  /*!
   * \brief invokes constructor, returns instance or 0 if trouble
   *
   * \param which_board	     Which USRP board on usb (not particularly useful; use 0)
   * \param fusb_block_size  fast usb xfer block size.  Must be a multiple of 512. 
   *                         Use zero for a reasonable default.
   * \param fusb_nblocks     number of fast usb URBs to allocate.  Use zero for a reasonable default. 
   */
  static usrp_basic_rx *make (int which_board,
			      int fusb_block_size=0,
			      int fusb_nblocks=0,
			      const std::string fpga_filename = "",
			      const std::string firmware_filename = ""
			      );

  // MANIPULATORS

  /*!
   * \brief tell the fpga the rate rx samples are coming from the A/D's
   *
   * div = fpga_master_clock_freq () / sample_rate
   *
   * sample_rate is determined by a myriad of registers
   * in the 9862.  That's why you have to tell us, so
   * we can tell the fpga.
   */
  bool set_fpga_rx_sample_rate_divisor (unsigned int div);

  /*!
   * \brief read data from the D/A's via the FPGA.
   * \p len must be a multiple of 512 bytes.
   *
   * \returns the number of bytes read, or -1 on error.
   *
   * If overrun is non-NULL it will be set true iff an RX overrun is detected.
   */
  int read (void *buf, int len, bool *overrun);

  // ACCESSORS

  //! sampling rate of A/D converter
  virtual long converter_rate() const { return fpga_master_clock_freq(); } // 64M
  long adc_rate() const { return converter_rate(); }
  long adc_freq() const { return converter_rate(); }   //!< deprecated method name

  /*!
   * \brief Return daughterboard ID for given Rx daughterboard slot [0,1].
   *
   * \param which_dboard	[0,1] which Rx daughterboard
   *
   * \return daughterboard id >= 0 if successful
   * \return -1 if no daugherboard
   * \return -2 if invalid EEPROM on daughterboard
   */
  int daughterboard_id (int which_dboard) const { return d_dbid[which_dboard & 0x1]; }

  // ----------------------------------------------------------------
  // routines for controlling the Programmable Gain Amplifier
  /*!
   * \brief Set Programmable Gain Amplifier (PGA)
   *
   * \param which	which A/D [0,3]
   * \param gain_in_db	gain value (linear in dB)
   *
   * gain is rounded to closest setting supported by hardware.
   *
   * \returns true iff sucessful.
   *
   * \sa pga_min(), pga_max(), pga_db_per_step()
   */
  bool set_pga (int which, double gain_in_db);

  /*!
   * \brief Return programmable gain amplifier gain setting in dB.
   *
   * \param which	which A/D [0,3]
   */
  double pga (int which) const;

  /*!
   * \brief Return minimum legal PGA gain in dB.
   */
  double pga_min () const { return 0.0; }

  /*!
   * \brief Return maximum legal PGA gain in dB.
   */
  double pga_max () const { return 20.0; }

  /*!
   * \brief Return hardware step size of PGA (linear in dB).
   */
  double pga_db_per_step () const { return 20.0 / 20; }

  /*!
   * \brief Write direction register (output enables) for pins that go to daughterboard.
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		value to write into register
   * \param mask		which bits of value to write into reg
   *
   * Each d'board has 16-bits of general purpose i/o.
   * Setting the bit makes it an output from the FPGA to the d'board.
   *
   * This register is initialized based on a value stored in the
   * d'board EEPROM.  In general, you shouldn't be using this routine
   * without a very good reason.  Using this method incorrectly will
   * kill your USRP motherboard and/or daughterboard.
   */
  bool _write_oe (int which_dboard, int value, int mask);

  /*!
   * \brief Write daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		value to write into register
   * \param mask		which bits of value to write into reg
   */
  bool write_io (int which_dboard, int value, int mask);

  /*!
   * \brief Read daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		output
   */
  bool read_io (int which_dboard, int *value);

  /*!
   * \brief Read daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \returns register value if successful, else READ_FAILED
   */
  int read_io (int which_dboard);

  /*!
   * \brief Write auxiliary digital to analog converter.
   *
   * \param which_dboard	[0,1] which d'board
   *    			N.B., SLOT_TX_A and SLOT_RX_A share the same AUX DAC's.
   *          			SLOT_TX_B and SLOT_RX_B share the same AUX DAC's.
   * \param which_dac		[2,3] TX slots must use only 2 and 3.
   * \param value		[0,4095]
   * \returns true iff successful
   */
  bool write_aux_dac (int which_board, int which_dac, int value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param which_dboard	[0,1] which d'board
   * \param which_adc		[0,1]
   * \param value		return 12-bit value [0,4095]
   * \returns true iff successful
   */
  bool read_aux_adc (int which_dboard, int which_adc, int *value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param which_dboard	[0,1] which d'board
   * \param which_adc		[0,1]
   * \returns value in the range [0,4095] if successful, else READ_FAILED.
   */
  int read_aux_adc (int which_dboard, int which_adc);

  /*!
   * \brief returns current fusb block size
   */
  int block_size() const;

  /*!
   * \brief Enable/disable automatic DC offset removal control loop in FPGA
   *
   * \param bits  which control loops to enable
   * \param mask  which \p bits to pay attention to
   *
   * If the corresponding bit is set, enable the automatic DC
   * offset correction control loop.
   *
   * <pre>
   * The 4 low bits are significant:
   *
   *   ADC0 = (1 << 0)
   *   ADC1 = (1 << 1)
   *   ADC2 = (1 << 2)
   *   ADC3 = (1 << 3)
   * </pre>
   *
   * By default the control loop is enabled on all ADC's.
   */
  bool set_dc_offset_cl_enable(int bits, int mask);

  // called in base class to derived class order
  bool start ();
  bool stop ();
};

/*!
 * \brief class for accessing the transmit side of the USRP
 */
class usrp_basic_tx : public usrp_basic 
{
private:
  fusb_devhandle	*d_devhandle;
  fusb_ephandle		*d_ephandle;
  int			 d_bytes_seen;		// how many bytes we've seen
  bool			 d_first_write;
  bool			 d_tx_enable;

 protected:
  int			 d_dbid[2];		// Tx daughterboard ID's

  /*!
   * \param which_board	     Which USRP board on usb (not particularly useful; use 0)
   * \param fusb_block_size  fast usb xfer block size.  Must be a multiple of 512.
   *                         Use zero for a reasonable default.
   * \param fusb_nblocks     number of fast usb URBs to allocate.  Use zero for a reasonable default.
   */
  usrp_basic_tx (int which_board,
		 int fusb_block_size=0,
		 int fusb_nblocks=0,
		 const std::string fpga_filename = "",
		 const std::string firmware_filename = ""
		 );		// throws if trouble

  bool set_tx_enable (bool on);
  bool tx_enable () const { return d_tx_enable; }

  bool disable_tx ();		// conditional disable, return prev state
  void restore_tx (bool on);	// conditional set

  void probe_tx_slots (bool verbose);
  int  dboard_to_slot (int dboard) { return (dboard << 1) | 0; }

public:

  ~usrp_basic_tx ();

  /*!
   * \brief invokes constructor, returns instance or 0 if trouble
   *
   * \param which_board	     Which USRP board on usb (not particularly useful; use 0)
   * \param fusb_block_size  fast usb xfer block size.  Must be a multiple of 512. 
   *                         Use zero for a reasonable default.
   * \param fusb_nblocks     number of fast usb URBs to allocate.  Use zero for a reasonable default. 
   */
  static usrp_basic_tx *make (int which_board, int fusb_block_size=0, int fusb_nblocks=0,
			      const std::string fpga_filename = "",
			      const std::string firmware_filename = ""
			      );

  // MANIPULATORS

  /*!
   * \brief tell the fpga the rate tx samples are going to the D/A's
   *
   * div = fpga_master_clock_freq () * 2
   *
   * sample_rate is determined by a myriad of registers
   * in the 9862.  That's why you have to tell us, so
   * we can tell the fpga.
   */
  bool set_fpga_tx_sample_rate_divisor (unsigned int div);

  /*!
   * \brief Write data to the A/D's via the FPGA.
   *
   * \p len must be a multiple of 512 bytes.
   * \returns number of bytes written or -1 on error.
   *
   * if \p underrun is non-NULL, it will be set to true iff
   * a transmit underrun condition is detected.
   */
  int write (const void *buf, int len, bool *underrun);

  /*
   * Block until all outstanding writes have completed.
   * This is typically used to assist with benchmarking
   */
  void wait_for_completion ();

  // ACCESSORS

  //! sampling rate of D/A converter
  virtual long converter_rate() const { return fpga_master_clock_freq () * 2; } // 128M
  long dac_rate() const { return converter_rate(); }
  long dac_freq() const { return converter_rate(); }	//!< deprecated method name

  /*!
   * \brief Return daughterboard ID for given Tx daughterboard slot [0,1].
   *
   * \return daughterboard id >= 0 if successful
   * \return -1 if no daugherboard
   * \return -2 if invalid EEPROM on daughterboard
   */
  int daughterboard_id (int which_dboard) const { return d_dbid[which_dboard & 0x1]; }

  // ----------------------------------------------------------------
  // routines for controlling the Programmable Gain Amplifier
  /*!
   * \brief Set Programmable Gain Amplifier (PGA)
   *
   * \param which	which D/A [0,3]
   * \param gain_in_db	gain value (linear in dB)
   *
   * gain is rounded to closest setting supported by hardware.
   * Note that DAC 0 and DAC 1 share a gain setting as do DAC 2 and DAC 3.
   * Setting DAC 0 affects DAC 1 and vice versa.  Same with DAC 2 and DAC 3.
   *
   * \returns true iff sucessful.
   *
   * \sa pga_min(), pga_max(), pga_db_per_step()
   */
  bool set_pga (int which, double gain_in_db);

  /*!
   * \brief Return programmable gain amplifier gain in dB.
   *
   * \param which	which D/A [0,3]
   */
  double pga (int which) const;

  /*!
   * \brief Return minimum legal PGA gain in dB.
   */
  double pga_min () const { return -20.0; }

  /*!
   * \brief Return maximum legal PGA gain in dB.
   */
  double pga_max () const { return 0.0; }

  /*!
   * \brief Return hardware step size of PGA (linear in dB).
   */
  double pga_db_per_step () const { return 20.0/255; }

  /*!
   * \brief Write direction register (output enables) for pins that go to daughterboard.
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		value to write into register
   * \param mask		which bits of value to write into reg
   *
   * Each d'board has 16-bits of general purpose i/o.
   * Setting the bit makes it an output from the FPGA to the d'board.
   *
   * This register is initialized based on a value stored in the
   * d'board EEPROM.  In general, you shouldn't be using this routine
   * without a very good reason.  Using this method incorrectly will
   * kill your USRP motherboard and/or daughterboard.
   */
  bool _write_oe (int which_dboard, int value, int mask);

  /*!
   * \brief Write daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		value to write into register
   * \param mask		which bits of value to write into reg
   */
  bool write_io (int which_dboard, int value, int mask);

  /*!
   * \brief Read daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \param value		return value
   */
  bool read_io (int which_dboard, int *value);

  /*!
   * \brief Read daughterboard i/o pin value
   *
   * \param which_dboard	[0,1] which d'board
   * \returns register value if successful, else READ_FAILED
   */
  int read_io (int which_dboard);

  /*!
   * \brief Write auxiliary digital to analog converter.
   *
   * \param which_dboard	[0,1] which d'board
   *    			N.B., SLOT_TX_A and SLOT_RX_A share the same AUX DAC's.
   *          			SLOT_TX_B and SLOT_RX_B share the same AUX DAC's.
   * \param which_dac		[2,3] TX slots must use only 2 and 3.
   * \param value		[0,4095]
   * \returns true iff successful
   */
  bool write_aux_dac (int which_board, int which_dac, int value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param which_dboard	[0,1] which d'board
   * \param which_adc		[0,1]
   * \param value		return 12-bit value [0,4095]
   * \returns true iff successful
   */
  bool read_aux_adc (int which_dboard, int which_adc, int *value);

  /*!
   * \brief Read auxiliary analog to digital converter.
   *
   * \param which_dboard	[0,1] which d'board
   * \param which_adc		[0,1]
   * \returns value in the range [0,4095] if successful, else READ_FAILED.
   */
  int read_aux_adc (int which_dboard, int which_adc);

  /*!
   * \brief returns current fusb block size
   */
  int block_size() const;

  // called in base class to derived class order
  bool start ();
  bool stop ();
};

#endif