L86 olvasása soros portról <problema lezarva>

Sziasztok.

Visszatert egy regi problemam, melyet annak idejen sem sikerult sem megmagyarazni, sem megoldani.

Raspberry A+ verzio, egy GNSS lapkaval a /dev/ttyAMA0-ra kotve.
Egy L90-assal mar sikerult egy B verzioju alaplapon mindent megoldanom, azota ahhoz hozza sem nyulok, mert meg elromlik... Szoval az alaplap most mas.

gpsd elindul, majd egy python scripttel olvasom az ama0-t:

#!/usr/bin/env python
# get lines of text from serial port, save them to a file

from __future__ import print_function
import serial, io

addr  = '/dev/ttyAMA0'  # serial port to read data from
baud  = 9600            # baud rate for serial port
fname = '/home/pi/gpslogger/gps-log/log.nmea'   # log file to save data in
fmode = 'a'             # log file mode = append
with serial.Serial(addr,9600) as pt, open(fname,fmode) as outf:
 spb = io.TextIOWrapper(io.BufferedRWPair(pt,pt,1),
  encoding='ascii', errors='ignore', newline='\r',line_buffering=True)
 spb.readline()  # throw away first line; likely to start mid-sentence (incomplete)
 while (1):
  x = spb.readline()  # read one line of text from serial port
  print (x,end='')    # echo line of text on-screen
  outf.write(x)       # write line of text to file
  outf.flush()        # make sure it actually gets written out

A kimeneti file egyenesen meses, termeszetesen hasznalhatatlan:

/home/pi/gpslogger/gps-log# cat log.nmea
IT b95)AGEbbb
9Q7EEU5zA9 5)GM!EI%59,V,,,,,0,060180,,,N*4F
$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32
$GPGGA,000028.799,,,,,0,0,,,M,,M,,*45
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,1,1,00*79
$GLGSV,1,1,00*65
$GPGLL,,,,,000028.799,V,N*77
$GPTXT,01,01,02,ANTSTATUS=OPEN*2B
$GPRMC,000029.79N*32
$GE
PGGA,000030.799,,,,,0,0,,,M,,M,,V,1,1,00*79
$GLGSV,1,1,GPGLL,,,,,000030.799,V,N*7E
PGGA,000031.799,V,1,1,00GPGLL,,,PEN*2B2
$GPRMC,0M,0.00,N,,,,0,0,V,1,1,00GPGLL,,,STATUS=O
$GPVTG,GSA,A,1,V,1,1,00GPGLL,,,$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,00.00,T,,,,,,0,0,.799,V,N$GPRMC,0M,0.00,N,,,,0,0,V,1,1,0000*65
0.00,T,,,,M,,M,,V,1,1,00GPGLL,,,PEN*2B,,,$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
0.00,T,,,,,,0,0,.799,V,N$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,STATUS=O
$GPVTG,*49
$GPGSV,1,1,TXT,01,0$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
0.00,T,,,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
0.00,T,,,,,,0,0,.799,V,N$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00G0.00,T,,,,,,0,0,GSV,1,1,.799,V,N$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
0.00,T,,,,M,,M,,V,1,1,00GPGLL,,,STATUS=O
$GPVTG,*4F
$GPGSV,1,1,,IJzLx=(IH
0
YYIII*-*JY0
wYYIL))II**
{
k
:(L))II**,II*-*JYX
/ZI,X:(I
{
k:(L))II**
wYYIsII*/yIHIH,
YYI
wYYI:(L))II**
wYYI:(
$GPTXT,01,01,02,ANTSTATUS=OPEN*2B
0.00,T,,114.799,E
$GPGS.799,V,N$GPRMC,0M,0.00,N,,M,,M,,GSV,1,1,TXT,01,0$GPRMC,0M,0.00,N*49
$GPGSV,1,1,TXT,01,0$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,00.00,T,,,,,,0,0,V,1,1,00GPGLL,,,PEN*2B
00120.790.00,T,,,,,,0,0,GSV,1,1,,,000120$GPRMC,00.00,T,,,,M,,M,,V,1,1,00GPGLL,,,00122.79,0.00,K,GSA,A,1,V,1,1,00GPGLL,,,$GPRMC,0,0.00,K,*4F
0.00,T,,,,,,0,0,GSV,1,1,*7BM,0.00,N,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
$GP0,060180PGGA,000E
$GPGS.799,V,N$GPRMC,0M,0.00,N,,M,,M,,V,1,1,00GPGLL,,,$GPRMC,00.00,T,,,,M,,M,,V,1,1,00GPGLL,,,PEN*0.00,T,,,,M,,M,,V,1,1,00GPGLL,,,PEN*2B
0.00,T,,,,,,0,0,GSV,1,1,,,000130PEN*2B
0.00,T,,,,,,0,0,V,1,1,0000*65
$$GPRMC,0,0.00,K,*4F
$GPGSV,1,1,TXT,01,0$GPRMC,00.00,T,,,,M,,M,,V,1,1,00GPGLL,,,PEN*2B

Szerintetek van erre magyarazat?