Serial Port access

[timfv]

I am attempting to access a serial port (for reading and writing) in a BaCon program under Linux. However, the documentation does not tell me how to accomplish this.
Is serial port access supported under BaCon? If not, are there any workarounds (shared libraries, etc) available?

[Pjot]

Hi timfv,

You might get this running with the "Columbo Simple Serial Library".

cssl.sourceforge.net

Regards
Peter

[Pjot]

Because I have some time left I hacked my way through this. First you need to compile the source file 'cssl.c' from the libcssl package as follows:

gcc -o libcssl.so cssl.c -shared -D_GNU_SOURCE -fPIC

Then take a look at the following code on how to use it. Make sure you use the correct device filename for your serial port. I use "/dev/ttyS0".

' Library name
lib$ = "./libcssl.so"

' LIB functions
IMPORT "cssl_geterror(void)" FROM lib$ TYPE int
IMPORT "cssl_geterrormsg(void)" FROM lib$ TYPE char*
IMPORT "cssl_start(void)" FROM lib$ TYPE void
IMPORT "cssl_stop(void)" FROM lib$ TYPE void
IMPORT "cssl_open(char*,void*,int,int,int,int,int)" FROM lib$ TYPE long
IMPORT "cssl_close(long)" FROM lib$ TYPE void
IMPORT "cssl_setup(long,int,int,int,int)" FROM lib$ TYPE void
IMPORT "cssl_setflowcontrol(long,int,int)" FROM lib$ TYPE void
IMPORT "cssl_putchar(long,char)" FROM lib$ TYPE void
IMPORT "cssl_putstring(long,char*)" FROM lib$ TYPE void
IMPORT "cssl_putdata(long,void*,int)" FROM lib$ TYPE void
IMPORT "cssl_drain(long)" FROM lib$ TYPE void
IMPORT "cssl_settimeout(long,int)" FROM lib$ TYPE void
IMPORT "cssl_getchar(long)" FROM lib$ TYPE int
IMPORT "cssl_getdata(long,void*,int)" FROM lib$ TYPE int

' Enumeration
CONST CSSL_OK = 0
CONST CSSL_ERROR_NOSIGNAL = 1
CONST CSSL_ERROR_NOTSTARTED = 2
CONST CSSL_ERROR_NULLPOINTER = 3
CONST CSSL_ERROR_OOPS = 4
CONST CSSL_ERROR_MEMORY = 5
CONST CSSL_ERROR_OPEN = 6

' Callback function
SUB callback
PRINT "Data arrived!"
END SUB

' Start library
cssl_start

' Open serial port
serial = cssl_open("/dev/ttyS0", callback, 1, 9600, 8, 0, 1)

' Send data
cssl_putstring(serial, "Hello world")

' Close port
cssl_close(serial)

' Stop library
cssl_stop


Hope this helps,
Peter

[timfv]

Thank you for your help. Unfortunately, this isn't fully functional. It seems to transmit data properly, but not receive, and the callback function doesn't appear to work at all. Do you have any further ideas on how to use the callback function (or configure the library to use blocking mode) under BaCon?

[Pjot]

Well, I am not a specialist with serial programming, nor with this library. Did you check the README file in the package where all functions are explained? You may need to fiddle around with 'cssl_drain()' for example.

There is a testprogram called "test.c" which appears to test the input from a serial keyboard. Below the conversion to BaCon FWIIW.


' Library name
lib$ = "./libcssl.so"

' LIB functions
IMPORT "cssl_geterror(void)" FROM lib$ TYPE int
IMPORT "cssl_geterrormsg(void)" FROM lib$ TYPE char* ALIAS cssl_geterrormsg$
IMPORT "cssl_start(void)" FROM lib$ TYPE void
IMPORT "cssl_stop(void)" FROM lib$ TYPE void
IMPORT "cssl_open(char*,void*,int,int,int,int,int)" FROM lib$ TYPE long
IMPORT "cssl_close(long)" FROM lib$ TYPE void
IMPORT "cssl_setup(long,int,int,int,int)" FROM lib$ TYPE void
IMPORT "cssl_setflowcontrol(long,int,int)" FROM lib$ TYPE void
IMPORT "cssl_putchar(long,char)" FROM lib$ TYPE void
IMPORT "cssl_putstring(long,char*)" FROM lib$ TYPE void
IMPORT "cssl_putdata(long,void*,int)" FROM lib$ TYPE void
IMPORT "cssl_drain(long)" FROM lib$ TYPE void
IMPORT "cssl_settimeout(long,int)" FROM lib$ TYPE void
IMPORT "cssl_getchar(long)" FROM lib$ TYPE int
IMPORT "cssl_getdata(long,void*,int)" FROM lib$ TYPE int

' Enumeration
CONST CSSL_OK = 0
CONST CSSL_ERROR_NOSIGNAL = 1
CONST CSSL_ERROR_NOTSTARTED = 2
CONST CSSL_ERROR_NULLPOINTER = 3
CONST CSSL_ERROR_OOPS = 4
CONST CSSL_ERROR_MEMORY = 5
CONST CSSL_ERROR_OPEN = 6

'---------------------------------------------------------------------

DECLARE finished
IMPORT pause(void) FROM "libc.so" TYPE int

' Example callback, it gets its id, buffer, and buffer length
SUB callback(int id, long buf[], int length)

LOCAL i

FOR i = 0 TO length

SELECT PEEK(buf[i])
' Ctrl-D
CASE 4
finished = 1
BREAK
' Replace \r with \n
CASE 13
buf[i] = 10
END SELECT

PRINT CHR$(buf[i])
NEXT

END SUB

cssl_start()

serial=cssl_open("/dev/ttyS0", callback, 0, 19200, 8, 0, 1)

IF serial = 0 THEN
PRINT cssl_geterrormsg$()
END -1
END IF

cssl_putstring(serial, "Type some data, ^D finishes.")

WHILE NOT(finished)
pause()
WEND

PRINT NL$, "^D - we exit", NL$

cssl_close(serial)
cssl_stop()


Regards
Peter

[volhout]

Hi Peter,

I tried your solution, but it does not work yet.
Let me explain, I am using Puppy linux (WARY 5.1.4.1) and have the devx SFS installed
I downloaded the CSSL package, compiled it.

I am using below code.


' Library name
lib$ = "./libcssl.so"

TRAP LOCAL

' LIB functions
IMPORT "cssl_geterror(void)" FROM lib$ TYPE int
IMPORT "cssl_geterrormsg(void)" FROM lib$ TYPE char*
IMPORT "cssl_start(void)" FROM lib$ TYPE void
IMPORT "cssl_stop(void)" FROM lib$ TYPE void
IMPORT "cssl_open(char*,void*,int,int,int,int,int)" FROM lib$ TYPE long
IMPORT "cssl_close(long)" FROM lib$ TYPE void
IMPORT "cssl_setup(long,int,int,int,int)" FROM lib$ TYPE void
IMPORT "cssl_setflowcontrol(long,int,int)" FROM lib$ TYPE void
IMPORT "cssl_putchar(long,char)" FROM lib$ TYPE void
IMPORT "cssl_putstring(long,char*)" FROM lib$ TYPE void
IMPORT "cssl_putdata(long,void*,int)" FROM lib$ TYPE void
IMPORT "cssl_drain(long)" FROM lib$ TYPE void
IMPORT "cssl_settimeout(long,int)" FROM lib$ TYPE void
IMPORT "cssl_getchar(long)" FROM lib$ TYPE int
IMPORT "cssl_getdata(long,void*,int)" FROM lib$ TYPE int

' Enumeration
CONST CSSL_OK = 0
CONST CSSL_ERROR_NOSIGNAL = 1
CONST CSSL_ERROR_NOTSTARTED = 2
CONST CSSL_ERROR_NULLPOINTER = 3
CONST CSSL_ERROR_OOPS = 4
CONST CSSL_ERROR_MEMORY = 5
CONST CSSL_ERROR_OPEN = 6

return$ = ""

' Callback function
SUB callback(int id, long buf[], int length)
   LOCAL i
   FOR i = 0 TO length
       return$ = CONCAT$(return$ , CHR$(buf[i]))
   NEXT
END SUB

' Start library
cssl_start

' Open serial port
serial = cssl_open("/dev/ttyS0", callback, 0, 300, 8, 0, 1)

' Send data
cssl_putstring(serial, "Hello world\n")

REPEAT
SLEEP 100
PRINT return$
UNTIL (INSTR(return$,"\n"))


' Close port
cssl_close(serial)

' Stop library
cssl_stop


I have following output when I connect the serial port input pin and output pin together as a sort of loopback function (as you can see, it almost works).
To do this connect pin 2 to pin 3 on the 9 pin serial port connector

# ./test0
H
He
Hel
Hell
Hello
Hello
Hello W
Hello Wo
Hello Wor
Hello Worl
Hello World
Hello World

#

I have following problems:
1/ The response is identical when I change the SLEEP 100 to SLEEP 10000
The SLEEP function does not do 10000 miliseconds.
2/ It does not work when I remove the SLEEP 100 command completely.
3/ I get only partial output when I increase the baudrate on the serial port. As if the data handling is too slow for the baudrate (below is for 9600 baud).

# ./test0
Ho
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
Hor
...........infinite

Any thought about this

Regards,

Volhout

[Pjot]

Hi volhout,

Well, this is the thing when using 3rd party open source libraries: these may contain bugs.

I guess best is to write a plain C program using this library to see if your objective can be achieved.

(1) If it still does not work, then either you may need to write your own serial port library, or you're stuck with command line utilities like 'setserial', 'tty', 'ioctl' and friends. These can be executed with EXEC$.

(2) But if such a C program works, then you can start porting it to BaCon.

Regards
Peter

[2lss]

Hi Everyone,

I don't think the problem lies in the library. I modified the test.c program (included in the cssl archive) and it works as expected. If I modify the bacon program to do the same thing, I get a strange output.

Examples (I have my microcontroller programmed to print "words lol lol" every second over ttyUSB0 @ 9600 baud)

test.c output:
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol


Bacon output:
w
o

r

d

s



l

o

l



l

o

l


It almost seems like extra blank characters are being printed. Perhaps the problem lies in CHR$?

Below are the programs

Bacon:
' Library name
lib$ = "./libcssl.so"

' LIB functions
IMPORT "cssl_geterror(void)" FROM lib$ TYPE int
IMPORT "cssl_geterrormsg(void)" FROM lib$ TYPE char* ALIAS cssl_geterrormsg$
IMPORT "cssl_start(void)" FROM lib$ TYPE void
IMPORT "cssl_stop(void)" FROM lib$ TYPE void
IMPORT "cssl_open(char*,void*,int,int,int,int,int)" FROM lib$ TYPE long
IMPORT "cssl_close(long)" FROM lib$ TYPE void
IMPORT "cssl_setup(long,int,int,int,int)" FROM lib$ TYPE void
IMPORT "cssl_setflowcontrol(long,int,int)" FROM lib$ TYPE void
IMPORT "cssl_putchar(long,char)" FROM lib$ TYPE void
IMPORT "cssl_putstring(long,char*)" FROM lib$ TYPE void
IMPORT "cssl_putdata(long,void*,int)" FROM lib$ TYPE void
IMPORT "cssl_drain(long)" FROM lib$ TYPE void
IMPORT "cssl_settimeout(long,int)" FROM lib$ TYPE void
IMPORT "cssl_getchar(long)" FROM lib$ TYPE int
IMPORT "cssl_getdata(long,void*,int)" FROM lib$ TYPE int

DECLARE finished
IMPORT pause(void) FROM "libc.so" TYPE int

' Enumeration
CONST CSSL_OK = 0
CONST CSSL_ERROR_NOSIGNAL = 1
CONST CSSL_ERROR_NOTSTARTED = 2
CONST CSSL_ERROR_NULLPOINTER = 3
CONST CSSL_ERROR_OOPS = 4
CONST CSSL_ERROR_MEMORY = 5
CONST CSSL_ERROR_OPEN = 6

finished = 0

' Callback function
SUB callback(int id, long buf[], int length)
LOCAL i
FOR i = 0 TO length
PRINT CHR$(buf[i])
NEXT  
END SUB

' Start library
cssl_start

' Open serial port
serial = cssl_open("/dev/ttyUSB0", callback, 0, 9600, 8, 0, 1)

IF serial = 0 THEN
   PRINT cssl_geterrormsg$()
   END -1
END IF

WHILE NOT(finished)
   pause()
WEND

' Send data
'cssl_putstring(serial, "Hello world")

' Close port
cssl_close(serial)

' Stop library
cssl_stop


test.c:
#include <stdio.h>#include <unistd.h>

#include "cssl.h"


/* if it is time to finish */
static int finished=0;


/* example callback, it gets its id, buffer, and buffer length */
static void callback(int id,
    uint8_t *buf,
    int length)
{
   int i;
// printf("Test\n");
   for(i=0;i<length;i++) {

// switch (buf[i]) {

// case 0x04:  /* Ctrl-D */
//    finished=1;
//    return;

// case '\r': /* replace \r with \n */
//    buf[i]='\n';

// }

putchar(buf[i]);
   }

   fflush(stdout);
}


int main()
{
   cssl_t *serial;

   cssl_start();
   
   serial=cssl_open("/dev/ttyUSB0",callback,0,
    9600,8,0,1);

   if (!serial) {
printf("%s\n",cssl_geterrormsg());
return -1;
   }

   //cssl_putstring(serial,"Type some data, ^D finishes.");

   while (!finished)
pause();

   printf("\n^D - we exit\n");

   cssl_close(serial);
   cssl_stop();

   return 0;
}


[Pjot]

The PRINT statement by default will ad a CR to any string it prints. So can you change the callback function to:

' Callback function
SUB callback(int id, long buf[], int length)
LOCAL i
FOR i = 0 TO length
PRINT CHR$(buf[i]);
NEXT
END SUB

...and try again?

Thanks,
Peter

[2lss]

That seems to do it, although I'm still getting a slightly strange output from the bacon version:

words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
worlol
words lol lolwords lol lol
words lol lol
words lol lol
words lol lol
words lol lol
wos lol lol
words lol lol
words lol lol
words lol lol
word lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol

The test.c program does not have this problem.

[Pjot]

That seems to do it, although I'm still getting a slightly strange output from the bacon version

The callback in the C program still is different compared to the BaCon version. This is some C code in the callback:

for(i=0;i<length;i++)


This means that the variable 'i' must be increased until but not including the variable 'length'.

However, the BaCon code says this:

FOR i = 0 TO length


But this actually includes the value of 'length' also.

Therefore, can you change the callback function once more to the following:

' Callback function
SUB callback(int id, long buf[], int length)
LOCAL i
FOR i = 0 TO length-1
PRINT CHR$(buf[i]);
NEXT
END SUB


And try again?

Regards
Peter

[2lss]

Ok. I changed the the FOR loop to 'length-1' and the output improved. However, there are still some issues with missing/wrong chatacters.

The first line is always screwed up.
�!!!!!!!!!!!!!!!!!!!!rds lol lol!!!!!!!!!!!��
words lol lol
words lol lol
words lol lol
words lol lol
'skip some lines'
words lol lol
words lol lol
words  lol
words lol lol
words lol lol
'repeat'


I did some investigating and decided to change 'long buf[]' to 'unsigned char buff[]'

So far it appears to be working correctly. ;D (although I'm not entirely sure why this is) I will let you know for sure after more testing.
./cssltest
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol
words lol lol


[Pjot]

So far it appears to be working correctly. ;D (although I'm not entirely sure why this is)

Indeed the second argument in the callback is defined as a pointer to a char, but by default I always translate pointers to long. In this case however, you use unsigned char, thereby omitting any relevance for a sign...

Well found!

Regards
Peter