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Forum Index : Microcontroller and PC projects : Picomite Serial Comm

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Bill.b

Senior Member

Joined: 25/06/2011
Location: Australia
Posts: 226
Posted: 03:11am 14 Mar 2024
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I am trying to send data to a DPplayer MP3 module.  The module is working OK when activated by a push button but does not respond to the serial comms input
I have used this module with picaxe in the past with great success

This is the picaxe coms used to send data the DPplayer.

SerOut TX, BAUD, ( $7E, $FF, $06, cmd, $00, arg.msb, arg.lsb, $EF )

Thepico program is

Option colourcode on
Option autorun on
Option DEFAULT NONE

dim integer CMD1,arg2

cmd1 = &h09   'Set SD card
arg2 = 0002
send
cmd1 = &h06  'Set volume
arg2 = 40
send
Do
cmd1 = &h12  'Play 0001.mp3
arg2 = 1
send
pause 1000
cmd1 = &h12  ' 'Play 0002.mp3
arg2 = 2
send
pause 1000
cmd1 = &h12   'Play 0003.mp3
send
pause 1000
loop

sub send
SetPin GP21, Gp20, com2
Open "com2:9600" As  #2
print #2,&h7E,&hFF,&h06,cmd1,&h00,00,arg2,&hEF
pause 100
arg2 = 0
close #2
end sub


Need help with the comms.

Bill
Edited 2024-03-14 13:12 by Bill.b
In the interests of the environment, this post has been constructed entirely from recycled electrons.
 
PhenixRising
Guru

Joined: 07/11/2023
Location: United Kingdom
Posts: 858
Posted: 03:30am 14 Mar 2024
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Suggest you start with bin2str (manual)

I use it a lot, along with str2bin  
 
Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3194
Posted: 03:42am 14 Mar 2024
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At first glance there are a few things that don't look right.  For a start, the commas in the PRINT statement will insert tab characters or spaces in the output which I doubt that you want.  Secondly, a constant like &h7E will be converted to a decimal number by the PRINT command which is not what you want.  Thirdly, you should add a semicolon at the end of the PRINT command to tell MMBasic to not append a CR/LF pair.

My guess is that you need something like this:
print #2, Chr$(&h7E) + Chr$(&hFF) + Chr$(&h06) + Chr$(cmd1) + Chr$(0) + Chr$(arg2) + Chr$(&hEF);

Also, why keep opening and closing the serial port?  It probably is not causing any trouble but normally you would leave it open while the program was running.

Geoff
Edited 2024-03-14 13:49 by Geoffg
Geoff Graham - http://geoffg.net
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2135
Posted: 03:47am 14 Mar 2024
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Is there a particular need to Open and Close COM2 in the Sub?
I usually set the pins and Open at the start of the program and Close at the end.

If it must be done in the Sub perhaps put a 30mS pause between Open and Print to ensure it is ready to take the data.
 
Turbo46

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Joined: 24/12/2017
Location: Australia
Posts: 1611
Posted: 03:50am 14 Mar 2024
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You need to convert the data to 8 bit ascii characters using the CHR$() function.

Try:
sub send
SetPin GP21, Gp20, com2
Open "com2:9600" As  #2
' print #2,&h7E,&hFF,&h06,cmd1,&h00,00,arg2,&hEF
print #2,chr$(&h7E),chr$(&hFF),chr$(&h06),chr$(cmd1),chr$(&h00),chr$(00),chr$(arg2),chr$(&hEF)
pause 100
arg2 = 0
close #2
end sub


Bill
Edited 2024-03-14 13:51 by Turbo46
Keep safe. Live long and prosper.
 
Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3194
Posted: 05:03am 14 Mar 2024
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  Turbo46 said  print #2,chr$(&h7E),chr$(&hFF),chr$(&h06),chr$(cmd1),chr$(&h00),chr$(00),chr$(arg2),chr$(&hEF)

No Bill, the commas (,) in the PRINT command will insert tabs or spaces.  Not what is intended.

My replacement PRINT command (above) was missing one character on the output.
I believe that this is what is required:
print #2, Chr$(&h7E) + Chr$(&hFF) + Chr$(&h06) + Chr$(cmd1) + Chr$(0) + Chr$(0) + Chr$(arg2) + Chr$(&hEF);

Geoff
Edited 2024-03-14 15:04 by Geoffg
Geoff Graham - http://geoffg.net
 
Turbo46

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Joined: 24/12/2017
Location: Australia
Posts: 1611
Posted: 05:25am 14 Mar 2024
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Of course. thanks.    I should have checked against some of my work.

I normally assemble the message first.

Txd$ = Chr$(&h7E) + Chr$(&hFF) + Chr$(&h06) + Chr$(cmd1) + Chr$(0) + Chr$(0) + Chr$(arg2) + Chr$(&hEF)
print #2 Txd$;

The semicolon suppresses the CR/LF

Bill
Keep safe. Live long and prosper.
 
Bill.b

Senior Member

Joined: 25/06/2011
Location: Australia
Posts: 226
Posted: 09:07am 14 Mar 2024
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Thank Geoff

Working OK now.

I closed the comms port as this is part of a program with an other comm port for a bluetooth HC-06 is included in the full program.

Bill
In the interests of the environment, this post has been constructed entirely from recycled electrons.
 
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