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flasherror
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Joined: 07/01/2019
Location: United States
Posts: 159

Posted: 06:42am 07 Jan 2019

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Hello,

I'm using MMBasic v4.5 on a Duinomite board and have a problem that I am stuck with, so posting here.

I need to send a specific sequence of bytes (some non ASCII) to serial port. All I want is to send a byte (or array of bytes) without MMBasic's "helpful" formatting features.

I want to do something like

print #3, data;

to send the actual value of the byte, not the ASCII representation. Furthermore, some of the bytes are non-printable ASCII values (for example byte = 0)
I understand that I can suppress CR/LF with using PRINT with semicolon at the end.
I can't use WRITE (with a string) because of the " automatic start/end quote prefixes.

The only thing I can think of is creating a string$ and storing values in it and then sending but I believe PRINT will not print non-printable values and would convert to ASCII chars anyway?

This is likely to be something simple that I am missing - but what? I have read the MMBasic manual multiple times and nothing stands out.

Turbo46

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Joined: 24/12/2017
Location: Australia
Posts: 1642

Posted: 07:15am 07 Jan 2019

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Welcome flasherror,

Do you mean something like this?

TXD$ = CHR$(RxAdd%)+CHR$(Fn%)+CHR$(BCnt%)+CHR$(In%)
PRINT #1, TXD$;

Bill

Keep safe. Live long and prosper.

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 07:30am 07 Jan 2019

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MMBasic strings can contain all 256 values ( 0 to 255)
It is one of the advantages when trying to send 'data' not just printable text.

Turbo64's code is all you need but for V4.5, ignore the % suffix

TXD$ = CHR$(RxAdd)+CHR$(Fn)+CHR$(BCnt)+CHR$(In)
PRINT #1, TXD$;

Jim

VK7JH
MMedit

Turbo46

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Joined: 24/12/2017
Location: Australia
Posts: 1642

Posted: 07:45am 07 Jan 2019

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Thanks Jim,

Too many Mites. I forgot the Duinomite is a Maximite beast.

Bill

Keep safe. Live long and prosper.

Grogster

Admin Group

Joined: 31/12/2012
Location: New Zealand
Posts: 9610

Posted: 09:21pm 07 Jan 2019

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I agree. I use this exact same method to send strings of non-printable bytes to various things. An example is the SMS module I use for cell-phone texting. You need to send a command that consists of the double-quote mark, and CTRL-Z to end the instruction. CTRL-Z is non-printable, and the double-quote is used by MMBASIC to define text, so you can't use that inside double-quotes!

MSG$="Hello. This is a test."
T$="AT+CMGS="+CHR$(34)+"012345678"+CHR$(34)+MSG$+CHR$(26)
Print #1,T$;

In this example, MSG$ is a plain old text message, and T$ builds the string to send to the SMS module, so it will text it to the cellphone. CHR$(34) is a double-quote("), and CHR$(26) is CTRL-Z.

MMBASIC has powerful string manipulation commands once you get stuck into the language.

Smoke makes things work. When the smoke gets out, it stops!

Turbo46

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Joined: 24/12/2017
Location: Australia
Posts: 1642

Posted: 10:35pm 07 Jan 2019

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Handy for escape codes too:

' Escape codes to clear the VT100 screen
SUB CLS2
PRINT #2, CHR$(27) "[2J" CHR$(27) "[H"
END SUB

And yes, as you can see from the above. Print will print non-printing characters.

Bill

Keep safe. Live long and prosper.

flasherror
Senior Member

Joined: 07/01/2019
Location: United States
Posts: 159

Posted: 12:42am 08 Jan 2019

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Thanks everyone. Use of string tested and working.

I was on the right track with the use of a string$ but didn't realize that print # would actually send the bytes (since printing to screen didn't).

I remember 80s basic programming and concatenation and the chr$(xx) tricks (still remember chr$(34) is " from memory)

However, in the event that MMBasic docs are updated it would be good idea to mention this use of string to send data directly. I was looking for an alternate PRINT command.

Is there a Wiki for MMbasic/the different *mite boards? Something that shows what language differences between MMbasic version (e.g. no SELECT CASE in v4.5). I'm thinking a wiki might complement digging through forum posts?

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