arch/arm/lib/board.c

   1 /*
   2  * (C) Copyright 2002-2006
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * (C) Copyright 2002
   6  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7  * Marius Groeger <mgroeger@sysgo.de>
   8  *
   9  * See file CREDITS for list of people who contributed to this
  10  * project.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  25  * MA 02111-1307 USA
  26  */
  27
  28 /*
  29  * To match the U-Boot user interface on ARM platforms to the U-Boot
  30  * standard (as on PPC platforms), some messages with debug character
  31  * are removed from the default U-Boot build.
  32  *
  33  * Define DEBUG here if you want additional info as shown below
  34  * printed upon startup:
  35  *
  36  * U-Boot code: 00F00000 -> 00F3C774  BSS: -> 00FC3274
  37  * IRQ Stack: 00ebff7c
  38  * FIQ Stack: 00ebef7c
  39  */
  40
  41 #include <common.h>
  42 #include <command.h>
  43 #include <malloc.h>
  44 #include <stdio_dev.h>
  45 #include <version.h>
  46 #include <net.h>
  47 #include <serial.h>
  48 #include <nand.h>
  49 #include <onenand_uboot.h>
  50 #include <mmc.h>
  51
  52 #ifdef CONFIG_BITBANGMII
  53 #include <miiphy.h>
  54 #endif
  55
  56 #ifdef CONFIG_DRIVER_SMC91111
  57 #include "../drivers/net/smc91111.h"
  58 #endif
  59 #ifdef CONFIG_DRIVER_LAN91C96
  60 #include "../drivers/net/lan91c96.h"
  61 #endif
  62
  63 DECLARE_GLOBAL_DATA_PTR;
  64
  65 ulong monitor_flash_len;
  66
  67 #ifdef CONFIG_HAS_DATAFLASH
  68 extern int  AT91F_DataflashInit(void);
  69 extern void dataflash_print_info(void);
  70 #endif
  71
  72 #ifdef CONFIG_DRIVER_RTL8019
  73 extern void rtl8019_get_enetaddr (uchar * addr);
  74 #endif
  75
  76 #if defined(CONFIG_HARD_I2C) || \
  77     defined(CONFIG_SOFT_I2C)
  78 #include <i2c.h>
  79 #endif
  80
  81
  82 /************************************************************************
  83  * Coloured LED functionality
  84  ************************************************************************
  85  * May be supplied by boards if desired
  86  */
  87 void inline __coloured_LED_init (void) {}
  88 void coloured_LED_init (void) __attribute__((weak, alias("__coloured_LED_init")));
  89 void inline __red_LED_on (void) {}
  90 void red_LED_on (void) __attribute__((weak, alias("__red_LED_on")));
  91 void inline __red_LED_off(void) {}
  92 void red_LED_off(void) __attribute__((weak, alias("__red_LED_off")));
  93 void inline __green_LED_on(void) {}
  94 void green_LED_on(void) __attribute__((weak, alias("__green_LED_on")));
  95 void inline __green_LED_off(void) {}
  96 void green_LED_off(void) __attribute__((weak, alias("__green_LED_off")));
  97 void inline __yellow_LED_on(void) {}
  98 void yellow_LED_on(void) __attribute__((weak, alias("__yellow_LED_on")));
  99 void inline __yellow_LED_off(void) {}
 100 void yellow_LED_off(void) __attribute__((weak, alias("__yellow_LED_off")));
 101 void inline __blue_LED_on(void) {}
 102 void blue_LED_on(void) __attribute__((weak, alias("__blue_LED_on")));
 103 void inline __blue_LED_off(void) {}
 104 void blue_LED_off(void) __attribute__((weak, alias("__blue_LED_off")));
 105
 106 /************************************************************************
 107  * Init Utilities                                                       *
 108  ************************************************************************
 109  * Some of this code should be moved into the core functions,
 110  * or dropped completely,
 111  * but let's get it working (again) first...
 112  */
 113
 114 #if defined(CONFIG_ARM_DCC) && !defined(CONFIG_BAUDRATE)
 115 #define CONFIG_BAUDRATE 115200
 116 #endif
 117 static int init_baudrate (void)
 118 {
 119         char tmp[64];   /* long enough for environment variables */
 120         int i = getenv_f("baudrate", tmp, sizeof (tmp));
 121
 122         gd->baudrate = (i > 0)
 123                         ? (int) simple_strtoul (tmp, NULL, 10)
 124                         : CONFIG_BAUDRATE;
 125
 126         return (0);
 127 }
 128
 129 static int display_banner (void)
 130 {
 131         printf ("\n\n%s\n\n", version_string);
 132         debug ("U-Boot code: %08lX -> %08lX  BSS: -> %08lX\n",
 133                _TEXT_BASE,
 134                _bss_start_ofs+_TEXT_BASE, _bss_end_ofs+_TEXT_BASE);
 135 #ifdef CONFIG_MODEM_SUPPORT
 136         debug ("Modem Support enabled\n");
 137 #endif
 138 #ifdef CONFIG_USE_IRQ
 139         debug ("IRQ Stack: %08lx\n", IRQ_STACK_START);
 140         debug ("FIQ Stack: %08lx\n", FIQ_STACK_START);
 141 #endif
 142
 143         return (0);
 144 }
 145
 146 /*
 147  * WARNING: this code looks "cleaner" than the PowerPC version, but
 148  * has the disadvantage that you either get nothing, or everything.
 149  * On PowerPC, you might see "DRAM: " before the system hangs - which
 150  * gives a simple yet clear indication which part of the
 151  * initialization if failing.
 152  */
 153 static int display_dram_config (void)
 154 {
 155         int i;
 156
 157 #ifdef DEBUG
 158         puts ("RAM Configuration:\n");
 159
 160         for(i=0; i<CONFIG_NR_DRAM_BANKS; i++) {
 161                 printf ("Bank #%d: %08lx ", i, gd->bd->bi_dram[i].start);
 162                 print_size (gd->bd->bi_dram[i].size, "\n");
 163         }
 164 #else
 165         ulong size = 0;
 166
 167         for (i=0; i<CONFIG_NR_DRAM_BANKS; i++) {
 168                 size += gd->bd->bi_dram[i].size;
 169         }
 170         puts("DRAM:  ");
 171         print_size(size, "\n");
 172 #endif
 173
 174         return (0);
 175 }
 176
 177 #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C)
 178 static int init_func_i2c (void)
 179 {
 180         puts ("I2C:   ");
 181         i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 182         puts ("ready\n");
 183         return (0);
 184 }
 185 #endif
 186
 187 #if defined(CONFIG_CMD_PCI) || defined (CONFIG_PCI)
 188 #include <pci.h>
 189 static int arm_pci_init(void)
 190 {
 191         pci_init();
 192         return 0;
 193 }
 194 #endif /* CONFIG_CMD_PCI || CONFIG_PCI */
 195
 196 /*
 197  * Breathe some life into the board...
 198  *
 199  * Initialize a serial port as console, and carry out some hardware
 200  * tests.
 201  *
 202  * The first part of initialization is running from Flash memory;
 203  * its main purpose is to initialize the RAM so that we
 204  * can relocate the monitor code to RAM.
 205  */
 206
 207 /*
 208  * All attempts to come up with a "common" initialization sequence
 209  * that works for all boards and architectures failed: some of the
 210  * requirements are just _too_ different. To get rid of the resulting
 211  * mess of board dependent #ifdef'ed code we now make the whole
 212  * initialization sequence configurable to the user.
 213  *
 214  * The requirements for any new initalization function is simple: it
 215  * receives a pointer to the "global data" structure as it's only
 216  * argument, and returns an integer return code, where 0 means
 217  * "continue" and != 0 means "fatal error, hang the system".
 218  */
 219 typedef int (init_fnc_t) (void);
 220
 221 int print_cpuinfo (void);
 222
 223 void __dram_init_banksize(void)
 224 {
 225         gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
 226         gd->bd->bi_dram[0].size =  gd->ram_size;
 227 }
 228 void dram_init_banksize(void)
 229         __attribute__((weak, alias("__dram_init_banksize")));
 230
 231 init_fnc_t *init_sequence[] = {
 232 #if defined(CONFIG_ARCH_CPU_INIT)
 233         arch_cpu_init,          /* basic arch cpu dependent setup */
 234 #endif
 235 #if defined(CONFIG_BOARD_EARLY_INIT_F)
 236         board_early_init_f,
 237 #endif
 238         timer_init,             /* initialize timer */
 239 #ifdef CONFIG_FSL_ESDHC
 240         get_clocks,
 241 #endif
 242         env_init,               /* initialize environment */
 243         init_baudrate,          /* initialze baudrate settings */
 244         serial_init,            /* serial communications setup */
 245         console_init_f,         /* stage 1 init of console */
 246         display_banner,         /* say that we are here */
 247 #if defined(CONFIG_DISPLAY_CPUINFO)
 248         print_cpuinfo,          /* display cpu info (and speed) */
 249 #endif
 250 #if defined(CONFIG_DISPLAY_BOARDINFO)
 251         checkboard,             /* display board info */
 252 #endif
 253 #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C)
 254         init_func_i2c,
 255 #endif
 256         dram_init,              /* configure available RAM banks */
 257         NULL,
 258 };
 259
 260 void board_init_f (ulong bootflag)
 261 {
 262         bd_t *bd;
 263         init_fnc_t **init_fnc_ptr;
 264         gd_t *id;
 265         ulong addr, addr_sp;
 266
 267         /* Pointer is writable since we allocated a register for it */
 268         gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR) & ~0x07);
 269         /* compiler optimization barrier needed for GCC >= 3.4 */
 270         __asm__ __volatile__("": : :"memory");
 271
 272         memset ((void*)gd, 0, sizeof (gd_t));
 273
 274         gd->mon_len = _bss_end_ofs;
 275
 276 #ifdef CONFIG_MACH_TYPE
 277         gd->bd->bi_arch_number = CONFIG_MACH_TYPE; /* board id for Linux */
 278 #endif
 279
 280         for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
 281                 if ((*init_fnc_ptr)() != 0) {
 282                         hang ();
 283                 }
 284         }
 285
 286         debug ("monitor len: %08lX\n", gd->mon_len);
 287         /*
 288          * Ram is setup, size stored in gd !!
 289          */
 290         debug ("ramsize: %08lX\n", gd->ram_size);
 291 #if defined(CONFIG_SYS_MEM_TOP_HIDE)
 292         /*
 293          * Subtract specified amount of memory to hide so that it won't
 294          * get "touched" at all by U-Boot. By fixing up gd->ram_size
 295          * the Linux kernel should now get passed the now "corrected"
 296          * memory size and won't touch it either. This should work
 297          * for arch/ppc and arch/powerpc. Only Linux board ports in
 298          * arch/powerpc with bootwrapper support, that recalculate the
 299          * memory size from the SDRAM controller setup will have to
 300          * get fixed.
 301          */
 302         gd->ram_size -= CONFIG_SYS_MEM_TOP_HIDE;
 303 #endif
 304
 305         addr = CONFIG_SYS_SDRAM_BASE + gd->ram_size;
 306
 307 #ifdef CONFIG_LOGBUFFER
 308 #ifndef CONFIG_ALT_LB_ADDR
 309         /* reserve kernel log buffer */
 310         addr -= (LOGBUFF_RESERVE);
 311         debug ("Reserving %dk for kernel logbuffer at %08lx\n", LOGBUFF_LEN, addr);
 312 #endif
 313 #endif
 314
 315 #ifdef CONFIG_PRAM
 316         /*
 317          * reserve protected RAM
 318          */
 319         i = getenv_r ("pram", (char *)tmp, sizeof (tmp));
 320         reg = (i > 0) ? simple_strtoul ((const char *)tmp, NULL, 10) : CONFIG_PRAM;
 321         addr -= (reg << 10);            /* size is in kB */
 322         debug ("Reserving %ldk for protected RAM at %08lx\n", reg, addr);
 323 #endif /* CONFIG_PRAM */
 324
 325 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
 326         /* reserve TLB table */
 327         addr -= (4096 * 4);
 328
 329         /* round down to next 64 kB limit */
 330         addr &= ~(0x10000 - 1);
 331
 332         gd->tlb_addr = addr;
 333         debug ("TLB table at: %08lx\n", addr);
 334 #endif
 335
 336         /* round down to next 4 kB limit */
 337         addr &= ~(4096 - 1);
 338         debug ("Top of RAM usable for U-Boot at: %08lx\n", addr);
 339
 340 #ifdef CONFIG_LCD
 341 #ifdef CONFIG_FB_ADDR
 342         gd->fb_base = CONFIG_FB_ADDR;
 343 #else
 344         /* reserve memory for LCD display (always full pages) */
 345         addr = lcd_setmem (addr);
 346         gd->fb_base = addr;
 347 #endif /* CONFIG_FB_ADDR */
 348 #endif /* CONFIG_LCD */
 349
 350         /*
 351          * reserve memory for U-Boot code, data & bss
 352          * round down to next 4 kB limit
 353          */
 354         addr -= gd->mon_len;
 355         addr &= ~(4096 - 1);
 356
 357         debug ("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10, addr);
 358
 359 #ifndef CONFIG_SPL_BUILD
 360         /*
 361          * reserve memory for malloc() arena
 362          */
 363         addr_sp = addr - TOTAL_MALLOC_LEN;
 364         debug ("Reserving %dk for malloc() at: %08lx\n",
 365                         TOTAL_MALLOC_LEN >> 10, addr_sp);
 366         /*
 367          * (permanently) allocate a Board Info struct
 368          * and a permanent copy of the "global" data
 369          */
 370         addr_sp -= sizeof (bd_t);
 371         bd = (bd_t *) addr_sp;
 372         gd->bd = bd;
 373         debug ("Reserving %zu Bytes for Board Info at: %08lx\n",
 374                         sizeof (bd_t), addr_sp);
 375         addr_sp -= sizeof (gd_t);
 376         id = (gd_t *) addr_sp;
 377         debug ("Reserving %zu Bytes for Global Data at: %08lx\n",
 378                         sizeof (gd_t), addr_sp);
 379
 380         /* setup stackpointer for exeptions */
 381         gd->irq_sp = addr_sp;
 382 #ifdef CONFIG_USE_IRQ
 383         addr_sp -= (CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ);
 384         debug ("Reserving %zu Bytes for IRQ stack at: %08lx\n",
 385                 CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ, addr_sp);
 386 #endif
 387         /* leave 3 words for abort-stack    */
 388         addr_sp -= 12;
 389
 390         /* 8-byte alignment for ABI compliance */
 391         addr_sp &= ~0x07;
 392 #else
 393         addr_sp += 128; /* leave 32 words for abort-stack   */
 394         gd->irq_sp = addr_sp;
 395 #endif
 396
 397         debug ("New Stack Pointer is: %08lx\n", addr_sp);
 398
 399 #ifdef CONFIG_POST
 400         post_bootmode_init();
 401         post_run (NULL, POST_ROM | post_bootmode_get(0));
 402 #endif
 403
 404         gd->bd->bi_baudrate = gd->baudrate;
 405         /* Ram ist board specific, so move it to board code ... */
 406         dram_init_banksize();
 407         display_dram_config();  /* and display it */
 408
 409         gd->relocaddr = addr;
 410         gd->start_addr_sp = addr_sp;
 411         gd->reloc_off = addr - _TEXT_BASE;
 412         debug ("relocation Offset is: %08lx\n", gd->reloc_off);
 413         memcpy (id, (void *)gd, sizeof (gd_t));
 414
 415         relocate_code (addr_sp, id, addr);
 416
 417         /* NOTREACHED - relocate_code() does not return */
 418 }
 419
 420 #if !defined(CONFIG_SYS_NO_FLASH)
 421 static char *failed = "*** failed ***\n";
 422 #endif
 423
 424 /************************************************************************
 425  *
 426  * This is the next part if the initialization sequence: we are now
 427  * running from RAM and have a "normal" C environment, i. e. global
 428  * data can be written, BSS has been cleared, the stack size in not
 429  * that critical any more, etc.
 430  *
 431  ************************************************************************
 432  */
 433
 434 void board_init_r (gd_t *id, ulong dest_addr)
 435 {
 436         char *s;
 437         bd_t *bd;
 438         ulong malloc_start;
 439 #if !defined(CONFIG_SYS_NO_FLASH)
 440         ulong flash_size;
 441 #endif
 442
 443         gd = id;
 444         bd = gd->bd;
 445
 446         gd->flags |= GD_FLG_RELOC;      /* tell others: relocation done */
 447
 448         monitor_flash_len = _end_ofs;
 449         /*
 450          * Enable D$:
 451          * I$, if needed, must be already enabled in start.S
 452          */
 453         dcache_enable();
 454
 455         debug ("monitor flash len: %08lX\n", monitor_flash_len);
 456         board_init();   /* Setup chipselects */
 457
 458 #ifdef CONFIG_SERIAL_MULTI
 459         serial_initialize();
 460 #endif
 461
 462         debug ("Now running in RAM - U-Boot at: %08lx\n", dest_addr);
 463
 464 #ifdef CONFIG_LOGBUFFER
 465         logbuff_init_ptrs ();
 466 #endif
 467 #ifdef CONFIG_POST
 468         post_output_backlog ();
 469 #endif
 470
 471         /* The Malloc area is immediately below the monitor copy in DRAM */
 472         malloc_start = dest_addr - TOTAL_MALLOC_LEN;
 473         mem_malloc_init (malloc_start, TOTAL_MALLOC_LEN);
 474
 475 #if !defined(CONFIG_SYS_NO_FLASH)
 476         puts ("Flash: ");
 477
 478         if ((flash_size = flash_init ()) > 0) {
 479 # ifdef CONFIG_SYS_FLASH_CHECKSUM
 480                 print_size (flash_size, "");
 481                 /*
 482                  * Compute and print flash CRC if flashchecksum is set to 'y'
 483                  *
 484                  * NOTE: Maybe we should add some WATCHDOG_RESET()? XXX
 485                  */
 486                 s = getenv ("flashchecksum");
 487                 if (s && (*s == 'y')) {
 488                         printf ("  CRC: %08X",
 489                                 crc32 (0, (const unsigned char *) CONFIG_SYS_FLASH_BASE, flash_size)
 490                         );
 491                 }
 492                 putc ('\n');
 493 # else  /* !CONFIG_SYS_FLASH_CHECKSUM */
 494                 print_size (flash_size, "\n");
 495 # endif /* CONFIG_SYS_FLASH_CHECKSUM */
 496         } else {
 497                 puts (failed);
 498                 hang ();
 499         }
 500 #endif
 501
 502 #if defined(CONFIG_CMD_NAND)
 503         puts ("NAND:  ");
 504         nand_init();            /* go init the NAND */
 505 #endif
 506
 507 #if defined(CONFIG_CMD_ONENAND)
 508         onenand_init();
 509 #endif
 510
 511 #ifdef CONFIG_GENERIC_MMC
 512        puts("MMC:   ");
 513        mmc_initialize(bd);
 514 #endif
 515
 516 #ifdef CONFIG_HAS_DATAFLASH
 517         AT91F_DataflashInit();
 518         dataflash_print_info();
 519 #endif
 520
 521         /* initialize environment */
 522         env_relocate ();
 523
 524 #if defined(CONFIG_CMD_PCI) || defined(CONFIG_PCI)
 525         arm_pci_init();
 526 #endif
 527
 528         /* IP Address */
 529         gd->bd->bi_ip_addr = getenv_IPaddr ("ipaddr");
 530
 531         stdio_init ();  /* get the devices list going. */
 532
 533         jumptable_init ();
 534
 535 #if defined(CONFIG_API)
 536         /* Initialize API */
 537         api_init ();
 538 #endif
 539
 540         console_init_r ();      /* fully init console as a device */
 541
 542 #if defined(CONFIG_ARCH_MISC_INIT)
 543         /* miscellaneous arch dependent initialisations */
 544         arch_misc_init ();
 545 #endif
 546 #if defined(CONFIG_MISC_INIT_R)
 547         /* miscellaneous platform dependent initialisations */
 548         misc_init_r ();
 549 #endif
 550
 551          /* set up exceptions */
 552         interrupt_init ();
 553         /* enable exceptions */
 554         enable_interrupts ();
 555
 556         /* Perform network card initialisation if necessary */
 557 #if defined(CONFIG_DRIVER_SMC91111) || defined (CONFIG_DRIVER_LAN91C96)
 558         /* XXX: this needs to be moved to board init */
 559         if (getenv ("ethaddr")) {
 560                 uchar enetaddr[6];
 561                 eth_getenv_enetaddr("ethaddr", enetaddr);
 562                 smc_set_mac_addr(enetaddr);
 563         }
 564 #endif /* CONFIG_DRIVER_SMC91111 || CONFIG_DRIVER_LAN91C96 */
 565
 566         /* Initialize from environment */
 567         if ((s = getenv ("loadaddr")) != NULL) {
 568                 load_addr = simple_strtoul (s, NULL, 16);
 569         }
 570 #if defined(CONFIG_CMD_NET)
 571         if ((s = getenv ("bootfile")) != NULL) {
 572                 copy_filename (BootFile, s, sizeof (BootFile));
 573         }
 574 #endif
 575
 576 #ifdef BOARD_LATE_INIT
 577         board_late_init ();
 578 #endif
 579
 580 #ifdef CONFIG_BITBANGMII
 581         bb_miiphy_init();
 582 #endif
 583 #if defined(CONFIG_CMD_NET)
 584 #if defined(CONFIG_NET_MULTI)
 585         puts ("Net:   ");
 586 #endif
 587         eth_initialize(gd->bd);
 588 #if defined(CONFIG_RESET_PHY_R)
 589         debug ("Reset Ethernet PHY\n");
 590         reset_phy();
 591 #endif
 592 #endif
 593
 594 #ifdef CONFIG_POST
 595         post_run (NULL, POST_RAM | post_bootmode_get(0));
 596 #endif
 597
 598 #if defined(CONFIG_PRAM) || defined(CONFIG_LOGBUFFER)
 599         /*
 600          * Export available size of memory for Linux,
 601          * taking into account the protected RAM at top of memory
 602          */
 603         {
 604                 ulong pram;
 605                 uchar memsz[32];
 606 #ifdef CONFIG_PRAM
 607                 char *s;
 608
 609                 if ((s = getenv ("pram")) != NULL) {
 610                         pram = simple_strtoul (s, NULL, 10);
 611                 } else {
 612                         pram = CONFIG_PRAM;
 613                 }
 614 #else
 615                 pram=0;
 616 #endif
 617 #ifdef CONFIG_LOGBUFFER
 618 #ifndef CONFIG_ALT_LB_ADDR
 619                 /* Also take the logbuffer into account (pram is in kB) */
 620                 pram += (LOGBUFF_LEN+LOGBUFF_OVERHEAD)/1024;
 621 #endif
 622 #endif
 623                 sprintf ((char *)memsz, "%ldk", (bd->bi_memsize / 1024) - pram);
 624                 setenv ("mem", (char *)memsz);
 625         }
 626 #endif
 627
 628         /* main_loop() can return to retry autoboot, if so just run it again. */
 629         for (;;) {
 630                 main_loop ();
 631         }
 632
 633         /* NOTREACHED - no way out of command loop except booting */
 634 }
 635
 636 void hang (void)
 637 {
 638         puts ("### ERROR ### Please RESET the board ###\n");
 639         for (;;);
 640 }