Serial Port/USB

To detect your USB serial link and obtain its USB number, you would need the information obtained with !USBDescriptor or !UsbInfo report just for this device.

Or from *USBDevices

The cheap USB-connected GPS devices are not supported by SerialUSB hence I am accessing them directly by their USB number.

It looks like you have done everything correctly in regards to the more expensive device (GlobalSat BU-353-S4 USB GPS Receiver). According to the GlobalSat manual, the device works only at 4800 baud rate, the correct OPENIN line is just as you have indicated. I use
“in% = OPENIN(”SerialUSB#baud=4800;stop=1;noparity;nohandshake;noblock:“)” the additional data=8 that you use also works just as well for me. It works on a PineBook, Pi-Top with Pi3B+, DeskPi Pro (as used in 4te2 and PiHarder) fitted with Pi4B clocked at 2GHz.

Before sending it back to the suppliers with a dead on arrival note, you should check that it is functioning correctly by trying it out on Windows. You can download the driver (Windows USB Driver) and simple app (GPS Info Tool For Windows) from the GlobalSat website https://www.globalsat.com.tw/en/a4-10593/BU-353S4.html.

Norman,, I agree with you, SerialUSB should work, but if you unplug and replug the port number is incremented ex: SerialUSB1.
The correct command to check it (Colin Granville) is: Filer_OpenDir Devices:$.

Hoping that the GlobalSat BU-353-S4 USB GPS Receiver module, is not out of order.
I must have a cheap GPS module, but I can’t find it anymore…tracking is missing :)

@Chris
I like your very elegant solution to the problem of using cheap USB devices. The good news is that the GlobalSat BU-353-S4 USB GPS Receiver also works with your program by changing the s$=“u-blox” to s$ = “Prolif”. I assume that all PL2303 would also work. Hopefully SatNav 2.54 will also will also work with Prolific GPS devices.

Hopefully, Yes. Not sure I would claim that it was elegant. It does have 9600 baud specified in the BASIC programme (but that would be easy to amend). The full list of changes is given below (the programme LineData also has similar changes in its initialisation rourine.

Comparing files z252.txt and Z254.TXT
***** z252.txt
!RunImage252 WR/WR   BASIC     09:47:24 05-Jul-2022  192 Kbytes
>LIST
***** Z254.TXT
!RunImage254 WR/WR   BASIC     18:20:54 08-Nov-2022  193 Kbytes
LineData254  WR/WR   BASIC     01:31:16 08-Nov-2022   40 Kbytes
>LIST
*****

***** z252.txt
   20:
   30REM This programme is SatNav and is version 2.52 (5-Jul-22)
   40ver$="2.52 (5-Jul-2022)"
   50copy$="©  C.K.Hall 2016."
***** Z254.TXT
   20:
   30REM This programme is SatNav and is version 2.54 (7-Nov-22)
   40ver$="2.54 (7-Nov-2022)"
   50copy$="©  C.K.Hall 2016."
*****

***** z252.txt
 savespr%=FALSE
  260:
***** Z254.TXT
 savespr%=FALSE
  251REM USB attached device
  252SYS "XOS_ReadVarVal","SatNav$USBDevice",,-1 TO ,,usbdev%
  253usbdev$="":fusb%=0:DIM ssbuf% 20
  254IF usbdev% THEN SYS "XOS_ReadVarVal","SatNav$USBDevice",qbuf%,190 TO ,,nob%,,r4%:IF r4%=0 THEN qbuf%?nob%=13:usbdev$=$qbuf
%:usbdev%=TRUE ELSE usbdev%=FALSE
  260:
*****

***** z252.txt
  730WHILE NOT(quit%) AND INKEY(-8)=0 AND but_quit%<>0
  740  SYS "Wimp_Poll",mask%,block% TO reason%
  750  REM  Dimension all the arrays
***** Z254.TXT
  730WHILE NOT(quit%) AND INKEY(-8)=0 AND but_quit%<>0
  731  REM Try pollidle
  732  SYS "OS_ReadMonotonicTime" TO mnt%
  740  SYS "Wimp_PollIdle",mask%,block%,mnt%+15 TO reason%
  750  REM  Dimension all the arrays
*****

***** z252.txt
 2360  REPEAT
 2370    SYS "OS_SerialOp",4,-1 TO ,r1% ;r2%
 2380    if%+=1
***** Z254.TXT
 2360  REPEAT
 2361    IF usbdev% THEN
 2362   REM   LOCAL ERROR
 2363   REM   ON ERROR LOCAL CLOSE#fusb%:fusb%=0:r1%=0:r2%=2
 2364      IF fusb% THEN
 2365        SYS "OS_GBPB",4,fusb%,ssbuf%,1 TO ,,fend%
 2366        IF ssbuf%=fend% THEN r1%=0:r2%=2 ELSE r1%=?ssbuf%:r2%=0
 2367      ELSE
 2368        r1%=0:r2%=2:serialOK%=FALSE
 2369      ENDIF
 2370   REM  RESTORE ERROR
 2371      IF fusb%=0 AND usbn% THEN fusb%=OPENIN("USB"+STR$(usbn%)+"#baud=9600;data=8;stop=1;noparity;nohandshake;noblock:")
 2372    ELSE
 2373      SYS "OS_SerialOp",4,-1 TO ,r1% ;r2%
 2374    ENDIF
 2380    if%+=1
*****

***** z252.txt
 3010    flag2$="NoSer"
 3020    *FX 21,1
 3030    SYS "OS_SerialOp",5,3,0:REM Baud rate to slow
***** Z254.TXT
 3010    flag2$="NoSer"
 3011   IF usbdev% THEN
 3012    REM USB connected - use *USBDevices to find unit
 3013    IF fusb% THEN CLOSE#fusb%:fusb%=0
 3014    OSCLI("USBDevices { > <SatNav$Dir>.DevList }")
 3015    usbdev%=OPENIN("<SatNav$Dir>.DevList")
 3016    a$=GET$#usbdev%
 3017    j%=INSTR(a$,"Description")
 3018    i%=0
 3019    usbn%=0
 3020    REPEAT
 3021      IF MID$(a$,j%,6)=usbdev$ THEN usbn%=VAL(MID$(a$,1,4))
 3022      a$=GET$#usbdev%
 3023    UNTIL EOF#usbdev%
 3024    CLOSE#usbdev%
 3025    IF usbn% THEN fusb%=OPENIN("USB"+STR$(usbn%)+"#baud=9600;data=8;stop=1;noparity;nohandshake;noblock:")
 3026   ELSE
 3028    *FX 21,1
 3029    fusb%=0
 3030    SYS "OS_SerialOp",5,3,0:REM Baud rate to slow
*****

***** z252.txt
 3080    SYS "OS_SerialOp",5,7,0:REM Baud rate to 9600
 3090    IF line$(1)="wkg" AND 1=3 THEN
***** Z254.TXT
 3080    SYS "OS_SerialOp",5,7,0:REM Baud rate to 9600
 3081   ENDIF
 3090    IF line$(1)="wkg" AND 1=3 THEN
*****

***** z252.txt
16950    flag2$="NoSer"
16960    *FX 21,1
16970    SYS "OS_SerialOp",5,3,0:REM Baud rate to slow
***** Z254.TXT
16950    flag2$="NoSer"
16951   IF usbdev% THEN
16952    REM USB connected - use *USBDevices to find unit
16953    IF fusb% THEN CLOSE#fusb%:fusb%=0
16954    OSCLI("USBDevices { > <SatNav$Dir>.DevList }")
16955    usbdev%=OPENIN("<SatNav$Dir>.DevList")
16956    a$=GET$#usbdev%
16957    j%=INSTR(a$,"Description")
16958    i%=0
16960    usbn%=0
16961    REPEAT
16962      IF MID$(a$,j%,6)=usbdev$ THEN usbn%=VAL(MID$(a$,1,4))
16963      a$=GET$#usbdev%
16964    UNTIL EOF#usbdev%
16965    CLOSE#usbdev%
16966    IF usbn% THEN fusb%=OPENIN("USB"+STR$(usbn%)+"#baud=9600;data=8;stop=1;noparity;nohandshake;noblock:")
16967   ELSE
16968    *FX 21,1
16970    SYS "OS_SerialOp",5,3,0:REM Baud rate to slow
*****

***** z252.txt
17020    SYS "OS_SerialOp",5,7,0:REM Baud rate to 9600
17030  ENDIF
***** Z254.TXT
17020    SYS "OS_SerialOp",5,7,0:REM Baud rate to 9600
17021   ENDIF
17030  ENDIF
*****

The routine for finding the USB device numbers will be handy, cant recall the details but some audio boxes start up with unusual interfaces and have to be programmed initially.
The expensive handheld garmin I bought was the last of that range to have real serial port.
I just wish we skipped the micro usb connector, I have various hardware socket and plug failures with them.
The USB C connector on my android tablet seems to be the most solid connection method so far.

To find the USB device number, if you know the VID & PID for the device, can you look for the sys var

USB$Device*VID_PID*

Yes, it would return the two values:

USB$Device_02_00_00_1546_01A7_-1_-1_0100_USB8 : 8
and
USB$Device_02_02_01_1546_01A7_01_00_0100_USB8 : 8 0 0

both of which evaluate to 8. When you unplug the device the system variable gets unset, even if you still have an endpoint open. If you plug it back in then it evaluates to a new USB number.

Nice one.

One reason I do it via the description field is that I have two devices from the same vendor that have different product IDs but the same first six characters of the description. With one set up I can use either device.

Not sure I would claim that it was elegant.

versatile perhaps?

@Chris
Thanks for posting the comparisons between 252 and 254. I have the GlobalSat BU-353-S4 USB GPS Receiver working with SatNav on my PineBook and also the DeskPi Pro. I could not see how usbdev$ got set and so I changed IF MID$(a$,j%,6)=usbdev$ to IF MID$(a$,j%,6)=“Prolif” According to the manual the device baud rate is 4800 but it seems to work okay at 9600.

One strange thing is that when I use Quit to close SatNav and then try to restart it, I get an Endpoint in use error in “Line Data: SVR line data and sprite data for text”

SatNav should close the input stream because unlike files you cannot open a stream more than once. Use the *SHUT command if you are not running anything else. By the time you get the endpoint in use error it no longer knows the file handle to close.

Raspberry Pico can be configured as a USBserial device, duly identified as such bij *USBDevices:

USB4 MicroPython
-——————-

Dev USB4 Info:

USB release : 0200
Device class : EF
Device subclass : 02
Device protocol : 01
Max packet size : 40
Vendor ID : 2E8A
Product ID : 0005
Device ID : 0100

1. of configs : 1
   Manufacturer : ‘MicroPython’
   Product : ‘Board in FS mode’
   Serial number : ‘000000000000’
   Speed : Full

Conf USB4 Info:

Current config : 1

1. of interfaces : 2
   Config value : 1
   Name : ’’
   Attributes : Bus powered
   Remote wakeup
   Maximum power : 250mA

Interface 0.0 class 2.2:0 ‘Board CDC’
Endpoint 1, Interrupt IN, 8 bytes 16 frames

Interface 1.0 class 10.0:0 ’’
Endpoint 2, Bulk OUT, 64 bytes 0 frames
Endpoint 2, Bulk IN, 64 bytes 0 frames

Raspberry Pico thus presents itself as CDC serial defice with 3 endpoints (Bulk IN, Bulk OUT and Control). Quite normal.
SerialUSB however does not recognise this CDC variety. Maybe its control protocol is somewhat deviant/special, but it is not at all a factory secret, and well documented. So I’m trying to implement it. But maybe Colin has already extended the SerialUSB module?

I don’t know whether the SerialUSB module is the right place to cope with this.
CDC is an open range. I just extended EtherUSB to cope with CDC Ethernet ECM variant.
But this is entirely different to the classical USB surf sticks. I accessed my old UMTS stick using the PPP module.
So perhaps the “Board CDC” can be accessed by PPP too?

I found this cdc open source driver code some time ago.
I /used/ to be able to convert google drive links for netsurf and wget. I changed the format a little and this works with wget
but Netsurf fails with the redirections involved. Any other browser (currently using slimjet) should download it.
If you haven’t got wget set up to find certificates you can use wget —no-check-certificates \URL\ -O new.zip
Using the .zip automatically sets the filetype on arrival.

In general USB devices which are acting a bit like a classical terminal (like a command shell or excepting AT commands as modems) can be accessed directly by reading and writing writing directly from/to the USB device. However compared to serial interfaces there is a subtile difference. Whilst a device can send characters at any time towards you USB bulk transfers requires that your program makes a “get data from device” inquiry.
Older programs as PPP are not behaving in such a way. So I wrote may years ago the USBDvEmu module which allows you to create a serial device behaviour from according USB devices. At that time there was no certain class for such devices so it tries to guess which USB endpoints are the right ones. USBDvEmu and its source can be downloaded from my homepage

http://thomas-milius-stade.dnshome.de/Download/Freeware/USBSDvEmu.zip

and

http://thomas-milius-stade.dnshome.de/Download/Open_Source/USBSDvEmu_c.zip

SatNav has been updated to version 2.56 and now uses USB connected GPS devices in preference to OS_SerialOp only whilst one is plugged in. It therefore works on a ‘plug and play’ basis allowing the GPS unit to be unplugged and plugged in again (which changes its enumeration) without raising an error. Most cheap GPS devices on Amazon should work. 9600baud is assumed.

Tested on a Pinebook Pro, it allows the device to be unplugged and plugged in again and SatNav continues working with no error, getting a GPS fix and calling on RiscOSM (if present, whether running or not so long as it has been ‘seen’ by the filer) to draw a map.

The relevant changes to the code are as follows:

Comparing files z252.txt and Z256.TXT
***** z252.txt
    1:  !RunImage252 WR/WR   BASIC     09:47:24 05-Jul-2022  192 Kbytes
    2:  >LIST
***** Z256.TXT
    1:  !RunImage256 WR/WR   BASIC     09:15:47 26-Apr-2023  193 kbytes
    2:  !RunImage254 WR/WR   BASIC     18:20:54 08-Nov-2022  193 Kbytes
    3:  >LIST
*****

***** z252.txt
  248:   2360  REPEAT
  249:   2370    SYS "OS_SerialOp",4,-1 TO ,r1% ;r2%
  250:   2380    if%+=1
  251:   2390    IF (r2% AND 2)=0 THEN
  252:   2400      REM Character in buffer (C clear)
***** Z256.TXT
  259:   2360  REPEAT
  260:   2361    SYS "XOS_ReadVarVal","USB$Device_02_00_00*",,-1 TO ,,usbdev%
  261:   2362    IF usbdev% THEN
  262:   2363      r4%=-1
  263:   2364      SYS "XOS_ReadVarVal","USB$Device_02_00_00*",qbuf%,256,0 TO ,,r2%,r3%,r4%
  264:   2365      IF r4%=0 THEN qbuf%?r2%=13:tusb%=VAL($qbuf%) ELSE tusb%=-1
  265:   2366      IF nusb%<>tusb% THEN
  266:   2367        REM close prev stream
  267:   2368        IF fusb% THEN CLOSE#fusb%:fusb%=0
  268:   2369        IF tusb%>0 THEN
  269:   2370          REM open new stream
  270:   2371          fusb%=OPENIN("USB"+STR$(tusb%)+"#baud=9600;data=8;stop=1;noparity;nohandshake;noblock:")
  271:   2372          nusb%=tusb%
  272:   2373        ENDIF
  273:   2374      ENDIF
  274:   2375      IF nusb%=tusb% THEN
  275:   2376        REM read bytes   -trap errors
  276:   2377        LOCAL ERROR
  277:   2378        ON ERROR LOCAL CLOSE#fusb%:fusb%=0:r1%=0:r2%=2
  278:   2379        IF fusb% THEN
  279:   2380          SYS "OS_GBPB",4,fusb%,ssbuf%,1 TO ,,fend%
  280:   2381          IF ssbuf%=fend% THEN r1%=0:r2%=2 ELSE r1%=?ssbuf%:r2%=0
  281:   2382        ELSE
  282:   2383          r1%=0:r2%=2:serialOK%=FALSE
  283:   2384        ENDIF
  284:   2385        RESTORE ERROR
  285:   2386      ENDIF
  286:   2391    ELSE
  287:   2392      SYS "OS_SerialOp",4,-1 TO ,r1% ;r2%
  288:   2393    ENDIF
  289:   2394    if%+=1
  290:   2395    IF (r2% AND 2)=0 THEN
  291:   2400      REM Character in buffer (C clear)
*****