akc6955.c

   1 /*
   2  * OpenI2CRADIO
   3  * RADIO CHIP AKC6955 Handler
   4  * Copyright (C) 2013-06-10 K.Ohta <whatisthis.sowhat ai gmail.com>
   5  * License: GPL2+LE
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2,
  10  *  or (at your option) any later version.
  11  *  This library / program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14  *  See the GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this library; see the file COPYING. If not, write to the
  18  *  Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA 02110-1301, USA.
  20  *
  21  *  As a special exception, if you link this(includeed from sdcc) library
  22  *  with other files, some of which are compiled with SDCC,
  23  *  to produce an executable, this library does not by itself cause
  24  *  the resulting executable to be covered by the GNU General Public License.
  25  *  This exception does not however invalidate any other reasons why
  26  *  the executable file might be covered by the GNU General Public License.
  27  */
  28
  29 #include <stdarg.h>
  30 #include <stdio.h>
  31 #ifdef __SDCC
  32 #include <delay.h>
  33 #else
  34 #include <xc.h>
  35 #endif
  36 #include <string.h>
  37 #include "akc6955.h"
  38 #include "i2c_io.h"
  39 #include "idle.h"
  40 #include "power.h"
  41 #include "commondef.h"
  42 #include "menu.h"
  43 #include "ui.h"
  44
  45 unsigned char akc6955_readcmd(unsigned char reg)
  46 {
  47    return i2c_read_byte(AKC6955_ADDRESS, reg);
  48 }
  49
  50 void akc6955_writecmd(unsigned char reg,unsigned char data)
  51 {
  52     i2c_send_byte(AKC6955_ADDRESS, reg, data);
  53 }
  54
  55 unsigned char akc6955_get_band(void)
  56 {
  57     return akc6955_readcmd(AKC6955_BAND);
  58 }
  59
  60 unsigned char akc6955_get_amband(void)
  61 {
  62    return akc6955_get_band() >> 3;
  63 }
  64
  65 unsigned char akc6955_get_fmband(void)
  66 {
  67    return akc6955_get_band() & 0x07;
  68 }
  69
  70
  71 void akc6955_chg_fm(unsigned char f, unsigned int freq)
  72 {
  73     __bitops_t b;
  74     b.byte = akc6955_readcmd(AKC6955_POWER);
  75     b.b6 = 0;
  76     if(f != 0){
  77         b.b6 = 1;
  78         akc6955_set_fmband(setup.fmband);
  79         akc6955_writecmd(AKC6955_POWER, b.byte);
  80         akc6955_set_freq(freq);
  81         return;
  82     }
  83     akc6955_writecmd(AKC6955_POWER, b.byte);
  84     akc6955_set_amband(setup.amband);
  85     akc6955_set_freq(freq);
  86
  87 }
  88
  89 unsigned char akc6955_get_fm(void)
  90 {
  91     __bitops_t b;
  92     b.byte = akc6955_readcmd(AKC6955_POWER);
  93     if(b.b6){
  94         return 0xff;
  95     }
  96     return 0;
  97 }
  98
  99
 100 void akc6955_set_amband(unsigned char band)
 101 {
 102     unsigned char b;
 103     unsigned char c;
 104
 105     c = RFAMP_SW;
 106     if((band < AKC6955_BAND_SW1) || (band == AKC6955_BAND_MW4)) {
 107         c = RFAMP_MWLW;
 108     }
 109     rfamp_power(c);
 110     b = akc6955_readcmd(AKC6955_BAND);
 111     b &= 0x07; // extract FM
 112     b = b | ((band & 0x1f) << 3);
 113     akc6955_writecmd(AKC6955_BAND, b);
 114     akc6955_do_tune();
 115 }
 116
 117 void akc6955_set_fmband(unsigned char band)
 118 {
 119     unsigned char b;
 120     rfamp_power(RFAMP_FM);
 121     b = akc6955_readcmd(AKC6955_BAND);
 122     b &= 0xf8; // extract AM
 123     b = b | (band & 0x07);
 124     akc6955_writecmd(AKC6955_BAND, b);
 125     akc6955_do_tune();
 126 }
 127
 128 void akc6955_set_power(unsigned char on)
 129 {
 130     __bitops_t b;
 131     b.byte = akc6955_readcmd(AKC6955_POWER);
 132     b.b7 = 0;
 133     if(on != 0){
 134         b.b7 = 1;
 135     }
 136     akc6955_writecmd(AKC6955_POWER, b.byte);
 137 }
 138
 139 void akc6955_do_tune(void)
 140 {
 141     __bitops_t b;
 142     b.byte = akc6955_readcmd(AKC6955_POWER) & 0b11001111;
 143 //    b.b5 = 0; // Tun = '0'
 144 //    b.b4 = 0; // Force abort scan.
 145     akc6955_writecmd(AKC6955_POWER, b.byte);
 146     idle_time_ms(1);
 147     // Need sleep?-> Need! this sequence re                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 fer from reference code.
 148     b.b5= 1; // Tun = '1'
 149     akc6955_writecmd(AKC6955_POWER, b.byte);
 150     idle_time_ms(1);
 151     b.b5 = 0;
 152     akc6955_writecmd(AKC6955_POWER, b.byte);
 153     idle_time_ms(8);
 154 }
 155
 156 unsigned char akc6955_tune(void)
 157 {
 158     __bitops_t b;
 159     b.byte = akc6955_readcmd(AKC6955_RCH_HI);
 160     if(b.b5) {
 161         return 0xff;
 162     }
 163     return 0;
 164 }
 165
 166
 167 void akc6955_mode3k(unsigned char flag)
 168 {
 169     __bitops_t b;
 170     b.byte = akc6955_readcmd(AKC6955_CH_LO);
 171     akc6955_writecmd(AKC6955_CH_LO, b.byte);
 172
 173     b.byte = akc6955_readcmd(AKC6955_CH_HI);
 174     b.b5 = 0;
 175     if(flag != 0){
 176         b.b5 = 1;
 177     }
 178     akc6955_writecmd(AKC6955_CH_HI, b.byte);
 179     akc6955_do_tune();
 180 }
 181
 182 unsigned char akc6955_get_mode3k(void)
 183 {
 184     __bitops_t c;
 185     c.byte = akc6955_readcmd(AKC6955_CNR_AM);
 186     if(c.b7) {
 187         return 0xff;
 188     }
 189     return 0;
 190 }
 191
 192 void akc6955_set_tune(unsigned char mode_3k, unsigned int ch)
 193 {
 194     unsigned char band;
 195     unsigned char f;
 196     __bitops_t b;
 197     unsigned int i = ch;
 198     unsigned int start, stop;
 199     unsigned char q;
 200
 201     while(akc6955_chk_donescan() == 0) { // Wait for before completed
 202         idle_time_35ms();
 203     }
 204     f = akc6955_get_fm();
 205     band = 0;
 206     if(f == 0){
 207         band = akc6955_get_amband();
 208         if(band == AKC6955_BAND_AMUSER){
 209             start = userband.am_usrbands[setup.am_userbandnum].start * 32;
 210             stop = userband.am_usrbands[setup.am_userbandnum].stop * 32;
 211         } else {
 212             if(mode_3k != 0) {
 213                 q = 3;
 214             } else {
 215                 q = 5;
 216             }
 217             start = ambands[band].start / q;
 218             stop  = ambands[band].end / q;
 219         }
 220     } else {
 221         band = akc6955_get_fmband();
 222         if(band == AKC6955_BAND_FMUSER){
 223             start = userband.fm_usrbands[setup.fm_userbandnum].start * 32;
 224             stop = userband.fm_usrbands[setup.fm_userbandnum].stop * 32;
 225         } else {
 226             start = ((fmbands[band].start - 3000) * 2) / 5;
 227             stop = ((fmbands[band].end - 3000) * 2) / 5;;
 228         }
 229     }
 230     if(i > stop) i = stop; // ADD
 231     if(i < start) i = start;
 232
 233     b.byte = i & 0xff;
 234     akc6955_writecmd(AKC6955_CH_LO, b.byte);
 235
 236     b.byte = i >> 8;
 237     b.b6 = 1;
 238     if(mode_3k != 0){
 239         b.b5 = 1; // Mode 3K ON
 240     }
 241     akc6955_writecmd(AKC6955_CH_HI, b.byte);
 242
 243     akc6955_do_tune();
 244 }
 245
 246 void akc6955_do_scan(unsigned char up)
 247 {
 248     __bitops_t b;
 249     unsigned char c;
 250
 251     //20130823 Need wait for scan/tune completed w/o SDCC 3.3.x.
 252 #ifndef __SDCC
 253     while(akc6955_chk_donescan() == 0)
 254     {
 255         if(pollkey_single_timeout(1, 0) == charcode_a) return;  // 23ms, if 'A' Abort.
 256     }
 257 #endif
 258     b.byte = akc6955_readcmd(AKC6955_POWER) & 0b11000111;
 259
 260 //    b.b3 = 0;
 261  //   b.b4 = 0;
 262 // 20130823 : Is this collect?
 263 #ifdef __SDCC
 264 //     b.b5 = 0;
 265     akc6955_writecmd(AKC6955_POWER, b.byte);
 266     idle_time_35ms();
 267 #endif
 268
 269     b.b5 = 1; // Tune 0->1.
 270     akc6955_writecmd(AKC6955_POWER, b.byte);
 271     idle_time_35ms();
 272
 273     b.b4 = 1;
 274     if(up != 0) {
 275         b.b3= 1;
 276     }
 277     akc6955_writecmd(AKC6955_POWER, b.byte); // Raise seek bit to '1'.
 278     idle_time_35ms();
 279 }
 280
 281 void akc6955_abort_scan(void)
 282 {
 283     __bitops_t b;
 284     b.byte = akc6955_readcmd(AKC6955_POWER);
 285     b.b4 = 0;
 286     akc6955_writecmd(AKC6955_POWER, b.byte); // Falldown seek bit to '0'.
 287 }
 288
 289 void akc6955_set_scanrate_fm(unsigned char rate)
 290 {
 291     unsigned char c;
 292     c = akc6955_readcmd(AKC6955_SPACE);
 293     c = (c & 0xcf) | ((rate & 0x03) << 4);
 294     akc6955_writecmd(AKC6955_SPACE, c);
 295 }
 296
 297 unsigned char akc6955_get_scanrate_fm(void)
 298 {
 299 //    unsigned char c;
 300 //    c = akc6955_readcmd(AKC6955_SPACE);
 301 //    c = (c & 0x30) >> 4;
 302    return (akc6955_readcmd(AKC6955_SPACE) & 0x30) >> 4;
 303 }
 304
 305 unsigned char akc6955_chk_donescan(void)
 306 {
 307     __bitops_t b;
 308     b.byte = akc6955_readcmd(AKC6955_RCH_HI);
 309     if(b.b6){
 310         return 0xff;
 311     }
 312     return 0;
 313 }
 314
 315 unsigned int akc6955_get_channel(void)
 316 {
 317     unsigned char h, l;
 318     unsigned int u;
 319     l = akc6955_readcmd(AKC6955_RCH_LO) ;
 320     h = akc6955_readcmd(AKC6955_RCH_HI) & 0x1f;
 321     return  (h << 8) | l;
 322 //    return u;
 323 }
 324
 325 /*
 326  * Get AM/FM Frequency: ret = KHz at AM, 10KHz @FM.
 327  */
 328 unsigned int akc6955_get_freq(void)
 329 {
 330     __bitops_t b;
 331     unsigned int i;
 332     unsigned int freq;
 333     unsigned char band;
 334     unsigned char q;
 335     unsigned char f;
 336
 337     f = akc6955_get_fm();
 338     i = akc6955_get_channel();
 339     if(f != 0){ // 25KHz
 340         freq = i * 2 + i / 2 + 3000; // freq' = 25*i[KHz] = (25 / 10) *i [10KHz]
 341     } else { // 5K
 342        b.byte = akc6955_readcmd(AKC6955_CH_HI);
 343        band = akc6955_get_amband();
 344        if((band == AKC6955_BAND_MW2) || (band == AKC6955_BAND_LW) || (b.b5)){
 345            q = 3;
 346        } else {
 347            q = 5;
 348        }
 349        freq = i * q;
 350     }
 351     return freq;
 352 }
 353
 354 void akc6955_set_freq(unsigned int freq)
 355 {
 356     unsigned int ch;
 357     __bitops_t mode3k;
 358     unsigned char band;
 359     unsigned char q;
 360     unsigned char f;
 361
 362     f = akc6955_get_fm();
 363     if(f != 0) { // FM
 364        band = akc6955_get_fmband();
 365        //        band &= 7;
 366        ch = ((freq - 3000) * 2) / 5;
 367     } else {
 368         band = akc6955_get_amband();
 369         mode3k.byte = akc6955_readcmd(AKC6955_CNR_AM);
 370         if((band == AKC6955_BAND_MW2) || (band == AKC6955_BAND_LW) || (mode3k.b7)){
 371             q = 3;
 372             mode3k.b7 = 1;
 373         } else {
 374             q = 5;
 375             mode3k.b7 = 0;
 376         }
 377         ch = freq / q;
 378     }
 379     akc6955_set_tune(mode3k.b7, ch);
 380 }
 381
 382 void akc6955_set_userband(unsigned char start, unsigned char stop, unsigned int ch, unsigned char mode3k)
 383 {
 384     unsigned char f;
 385
 386     f = akc6955_get_fm();
 387     akc6955_writecmd(AKC6955_UCH_ST, start);
 388     akc6955_writecmd(AKC6955_UCH_EN, stop);
 389     if(f != 0){
 390         akc6955_set_fmband(AKC6955_BAND_FMUSER);
 391     } else {
 392         akc6955_set_amband(AKC6955_BAND_AMUSER);
 393     }
 394     akc6955_set_tune(mode3k, ch);
 395 }
 396
 397
 398 unsigned char akc6955_get_cnr(void)
 399 {
 400     unsigned char f;
 401     __bitops_t b;
 402     f = akc6955_get_fm();
 403     if(f != 0) { // FM
 404         b.byte = akc6955_readcmd(AKC6955_CNR_FM);
 405     } else { // AM
 406         b.byte = akc6955_readcmd(AKC6955_CNR_AM);
 407     }
 408     b.b7 = 0;
 409     return b.byte;
 410 }
 411
 412 int akc6955_read_level(void)
 413 {
 414     unsigned char f;
 415     unsigned char rflevel, iflevel;
 416     unsigned char b;
 417     int rssi;
 418     unsigned char band;
 419     int totallevel;
 420     int level;
 421
 422     f = akc6955_get_fm();
 423     b =  akc6955_readcmd(AKC6955_PGALEVEL);
 424     rflevel = (b & 0xe0) >> 5;
 425     iflevel = (b & 0x1c) >> 2;
 426     totallevel = rflevel + iflevel;
 427
 428     rssi = (int)(akc6955_readcmd(AKC6955_RSSI) & 0x7f);
 429     level = (int)(totallevel * 6 + rssi);
 430     if(f != 0){
 431         level = 103 - level; // totallevel * 6
 432     } else {
 433         band = akc6955_get_amband();
 434         if((band >= AKC6955_BAND_SW1) && (band <= AKC6955_BAND_AMUSER)) { // SW
 435             level = 103 - level;
 436         } else { //  MW,LW
 437             level = 123 - level;
 438         }
 439     }
 440     return level;
 441 }
 442
 443
 444 // Get diff. unit = 100Hz.
 445 int akc6955_get_diff(void)
 446 {
 447     __bitops_t diff;
 448     unsigned char f;
 449     int n;
 450
 451     diff.byte = akc6955_readcmd(AKC6955_FDNUM);
 452     if(diff.b7) {
 453         diff.b7 = 0;
 454         n = -((int) diff.byte);
 455     } else {
 456         diff.b7 = 0;
 457         n = (int)diff.byte;
 458     }
 459
 460     f = akc6955_get_fm();
 461     if(f != 0) { // FM
 462         return n * 10;
 463     }
 464     return n; // 10n
 465 }
 466
 467 void akc6955_up_freq(unsigned int step)
 468 {
 469     unsigned int freq;
 470 //    __bitops_t mode3k;
 471     unsigned char mode3k;
 472
 473     freq = akc6955_get_channel();
 474     freq += step;
 475 //    mode3k.byte = akc6955_readcmd(AKC6955_CNR_AM);
 476 //    akc6955_set_tune(mode3k.b7, freq);
 477     mode3k = akc6955_get_mode3k();
 478     akc6955_set_tune(mode3k, freq);
 479 }
 480
 481
 482 void akc6955_down_freq(unsigned int step)
 483 {
 484     unsigned int freq;
 485     unsigned char mode3k;
 486
 487     freq = akc6955_get_channel();
 488     if(freq <= step) return;
 489     freq -= step;
 490 //    mode3k.byte = akc6955_readcmd(AKC6955_CNR_AM);
 491     mode3k = akc6955_get_mode3k();
 492     akc6955_set_tune(mode3k, freq);
 493 }
 494
 495 void akc6955_setvolumemode(unsigned char flag)
 496 {
 497     __bitops_t c;
 498     c.byte = akc6955_readcmd(AKC6955_ENABLE);
 499     c.b3 = 0;
 500     if(flag != 0x00){
 501         c.b3 = 1;
 502     }
 503     akc6955_writecmd(AKC6955_ENABLE, c.byte);
 504 }
 505
 506 unsigned char akc6955_getvolumemode(void)
 507 {
 508     __bitops_t c;
 509     c.byte = akc6955_readcmd(AKC6955_ENABLE);
 510     if(c.b3){
 511         return 0xff;
 512     }
 513     return 0;
 514 }
 515
 516 void akc6955_setvolume(unsigned char level)
 517 {
 518 //    unsigned char c;
 519 //    c = akc6955_readcmd(AKC6955_VOLUME) & 0x03;
 520     if(level > 63) level = 63;
 521     akc6955_writecmd(AKC6955_VOLUME, ((akc6955_readcmd(AKC6955_VOLUME) & 0x03) | (level << 2)));
 522 }
 523
 524 unsigned char akc6955_getvolume(void)
 525 {
 526     unsigned char c;
 527     c = akc6955_readcmd(AKC6955_VOLUME) >> 2;
 528     return c;
 529 }
 530
 531 void akc6955_set_prevolume(unsigned char level)
 532 {
 533     unsigned char c;
 534     c = akc6955_readcmd(AKC6955_PRE) & 0xf3;
 535     c |= ((level & 0x03) << 2);
 536     akc6955_writecmd(AKC6955_PRE, c);
 537 }
 538
 539 unsigned char akc6955_get_prevolume(void)
 540 {
 541     unsigned char c;
 542 //    c = akc6955_readcmd(AKC6955_PRE) & 0x0c;
 543  //   c >>= 2;
 544     return (akc6955_readcmd(AKC6955_PRE) & 0x0c) >> 2;
 545 }
 546
 547
 548 void akc6955_setphase(unsigned char flag)
 549 {
 550     __bitops_t c;
 551     c.byte = akc6955_readcmd(AKC6955_VOLUME);
 552
 553     c.b0 = 1;
 554     if(flag == 0) {
 555         c.b0 = 0; //
 556     }
 557     akc6955_writecmd(AKC6955_VOLUME, c.byte);
 558 }
 559
 560 void akc6955_setline(unsigned char flag)
 561 {
 562     __bitops_t c;
 563     c.byte = akc6955_readcmd(AKC6955_VOLUME);
 564     c.b1 = 1;
 565     if(flag == 0) {
 566         c.b1 = 0;
 567     }
 568     akc6955_writecmd(AKC6955_VOLUME, c.byte);
 569 }
 570
 571 void akc6955_set_lowboost(unsigned char flag)
 572 {
 573     __bitops_t c;
 574     c.byte = akc6955_readcmd(AKC6955_STEREO);
 575     c.b3 = 1;
 576     if(flag == 0) {
 577         c.b3 = 0;
 578     }
 579     akc6955_writecmd(AKC6955_STEREO, c.byte);
 580 }
 581
 582 void akc6955_set_stereomode(unsigned char mode)
 583 {
 584     unsigned char c;
 585     c = akc6955_readcmd(AKC6955_STEREO);
 586     mode = (mode & 0x03) << 2;
 587     c = (c & 0xf3) | mode;
 588     akc6955_writecmd(AKC6955_STEREO, c);
 589 }
 590
 591 unsigned char akc6955_get_stereo(void)
 592 {
 593  //   unsigned char c;
 594 //    c = akc6955_readcmd(AKC6955_RCH_HI) & 0x80;
 595     return akc6955_readcmd(AKC6955_RCH_HI) & 0x80;
 596 }
 597
 598 /*
 599  * Get battery level.
 600  * Unit = 0.01V
 601  */
 602
 603 unsigned int akc6955_get_battery(void)
 604 {
 605     unsigned int batt;
 606     unsigned char c;
 607     c = akc6955_readcmd(AKC6955_VBAT) & 0x3f;
 608     batt = 180 + c * 5;
 609     return batt;
 610 }
 611
 612 /*
 613  * Misc
 614  */
 615 void akc6955_set_fmbandwidth(unsigned char bw)
 616 {
 617    unsigned char c = akc6955_readcmd(AKC6955_STEREO);
 618    c = (c & 0xfc) | (bw & 0x03);
 619    akc6955_writecmd(AKC6955_STEREO, c);
 620 }
 621
 622 unsigned char akc6955_get_fmbandwidth(void)
 623 {
 624     return (akc6955_readcmd(AKC6955_STEREO) & 0x03);
 625 }
 626
 627
 628
 629 void akc6955_set_thresh_fmstereo(unsigned char a)
 630 {
 631     unsigned char b;
 632     a = a & 0x03;
 633     setup.threshold_fmstereo = a;
 634     b = akc6955_readcmd(AKC6955_THRESH) & 0xfc;
 635     akc6955_writecmd(AKC6955_THRESH, a | b);
 636 }
 637
 638 void akc6955_set_thresh_width(unsigned char a)
 639 {
 640     unsigned char b;
 641     a = a & 0x03;
 642     setup.threshold_width = a;
 643     a = a << 2; // << 2
 644     b = akc6955_readcmd(AKC6955_THRESH) & 0xf3;;
 645     akc6955_writecmd(AKC6955_THRESH, a | b);
 646 }
 647
 648 void akc6955_set_thresh_amcnr(unsigned char a)
 649 {
 650     unsigned char b;
 651     a = a & 0x03;
 652     setup.threshold_amcnr = a;
 653     a = a << 4; // << 4
 654     b = akc6955_readcmd(AKC6955_THRESH) & 0xcf;
 655     akc6955_writecmd(AKC6955_THRESH, a | b);
 656 }
 657
 658 void akc6955_set_thresh_fmcnr(unsigned char a)
 659 {
 660     unsigned char b;
 661     a = a & 0x03;
 662     setup.threshold_fmcnr = a;
 663     a = a << 6; // << 4
 664     b = akc6955_readcmd(AKC6955_THRESH) & 0x3f;
 665     akc6955_writecmd(AKC6955_THRESH, a | b);
 666 }