   trace.begin(&uart, PSTR("CosaFAT16: started"));
   TRACE(free_memory());
   TRACE(sizeof(FAT16::File));
+  TRACE(CLOCK);
   ASSERT(sd.begin(CLOCK));
   ASSERT(FAT16::begin(&sd));
 }

  ASSERT(true == false);
}

/*
---------------------------------------------------------
CLOCK = SLOW_CLOCK
---------------------------------------------------------
CosaFAT16: started
free_memory() = 7080
sizeof(FAT16::File) = 18
NISSE.TXT     2013-12-13 10:32:48 13

Open file:7 ms
NISSE.TXT     2013-12-13 10:32:48 13
TMP.TXT       2000-01-01 01:00:00 0

Write file (8 KByte):138 ms

Close file:27 ms
NISSE.TXT     2013-12-13 10:32:48 13
TMP.TXT       2000-01-01 01:00:00 8192

Read file (8 KByte):62 ms

Remove file:33 ms
NISSE.TXT     2013-12-13 10:32:48 13

Open/Write/Close file:73 ms
Nisse badar.
Open/Read/Close file:4 ms

137:void loop():assert:true == false
---------------------------------------------------------
CLOCK = FAST_CLOCK
---------------------------------------------------------
CosaFAT16: started
free_memory() = 7080
sizeof(FAT16::File) = 18
NISSE.TXT     2013-12-13 10:32:48 13

Open file:6 ms
NISSE.TXT     2013-12-13 10:32:48 13
TMP.TXT       2000-01-01 01:00:00 0

Write file (8 KByte):128 ms

Close file:16 ms
NISSE.TXT     2013-12-13 10:32:48 13
TMP.TXT       2000-01-01 01:00:00 8192

Read file (8 KByte):53 ms

Remove file:30 ms
NISSE.TXT     2013-12-13 10:32:48 13

Open/Write/Close file:62 ms
Nisse badar.
Open/Read/Close file:4 ms

137:void loop():assert:true == false
*/

  ASSERT(file.is_open());
  char msg[] = "Nisse badar.\n";
  size = strlen(msg);
  ASSERT(file.write(msg, strlen(msg)) == (int) size);
  ASSERT(file.close());
  stop = RTC::millis();
  trace << PSTR("Open/Write/Close file:");
