GPS Project: PIC18F26K22 or PIC18F46K22

**astanapane** · - 11th July 2018, 08:18

Originally Posted by HenrikOlsson

Yes, you can have different baudrate(s) on different UARTs and yes you can change it at any time you want. But, as the posts in the other thread says, to change it you can't use PBPs DEFINE HSER_BAUD because that's a compile time directive and not a runtime command.

If you want to set or change the baudrate at runtime you need to set or change the registers manually. BAUDCON, SPBRG, SPBRGH most of the time. And remember that the register names are different for the second UART - BAUDCON2, SPBRG2 etc.

Without seeing your code we can't say why what you did didn't work.

Hi Henrik,

i did have the DEFINEs on the code like this.

Code:

'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 1 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|

        DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
        DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1
        DEFINE HSER_CLROERR 1 ' Clear overflow automatically
        DEFINE HSER_SPBRG 160 ' 38400 Baud @ 64MHz, -0,08%
        SPBRGH = 1
        BAUDCON.3 = 1         ' Enable 16 bit baudrate generator

        



        
'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 2 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|

        'DEFINE HSER2_RCSTA 90h ' Enable serial port & continuous receive
        'DEFINE HSER2_TXSTA 24h ' Enable transmit, BRGH = 1
        'DEFINE HSER2_CLROERR 1 ' Clear overflow automatically
        'DEFINE HSER2_SPBRG 160 ' 38400 Baud @ 64MHz, -0,08%
        'SPBRGH2 = 1
        'BAUDCON2.3 = 1         ' Enable 16 bit baudrate generator

        DEFINE HSER2_RCSTA 90h ' Enable serial port & continuous receive
        DEFINE HSER2_TXSTA 24h ' Enable transmit, BRGH = 1
        DEFINE HSER2_CLROERR 1 ' Clear overflow automatically
        DEFINE HSER2_SPBRG 130 ' 9600 Baud @ 64MHz, -0,02%
        SPBRGH2 = 6
        BAUDCON2.3 = 1         ' Enable 16 bit baudrate generator
        

'------------------------------------------------------------------------------|
'-----------sent a sentence to gps, this is not working at the moment----------|
'------------------------------------------------------------------------------|
' When the GPS Module is POWERED ON, then the following sentenses are received. 

'          $PMTK011,MTKGPS*08
'          $PMTK010,001*2E
'          $PMTK010,002*2D   

pause 800 
HSEROUT2 ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration
pause 500
RCSTA2 = $90 ' Enable serial port & continuous receive
TXSTA2 = $24 ' Enable transmit, BRGH = 1
SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz

On the first stage that i send the following command, to change the baudrate for the GPS, it works because both PIC and GPS are at the same rate.

Code:

B]HSEROUT2[/B] ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration

then i guess with the following code that i change the rate on the PIC's port.

Code:

RCSTA2 = $90 ' Enable serial port & continuous receive
TXSTA2 = $24 ' Enable transmit, BRGH = 1
SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%

then send the command which seems that it doesnt work.

Code:

HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz

**richard** · - 11th July 2018, 08:34

if you are using the 16 bit baudrate generator
BAUDCON2.3 = 1 ' Enable 16 bit baudrate generator

then the baud rate is set using SPBRGHx and SPBRGx

setting

Code:

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%

is only half the job

**astanapane** · - 11th July 2018, 08:44

Originally Posted by richard

if you are using the 16 bit baudrate generator
BAUDCON2.3 = 1 ' Enable 16 bit baudrate generator

then the baud rate is set using SPBRGHx and SPBRGx

setting

Code:

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%

is only half the job

I will check the code later today based on your given directions. thanks a lot.

I might need to check and wait for the GPS responds and PIC port response. I will try to set a code, and if i need again your help i will keep you posted.

**astanapane** · - 11th July 2018, 13:08

Dear all,

i did the following....

Code:

'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 1 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|
        
        RCSTA = $90 ' Enable serial port & continuous receive
        TXSTA = $24 ' Enable transmit, BRGH = 1
        'CLROERR = 1 ' Clear overflow automatically
        SPBRG = 160 ' 38400 Baud @ 64MHz, -0,08%
        SPBRGH = 1
        BAUDCON.3 = 1         ' Enable 16 bit baudrate generator
        
'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 2 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|

        RCSTA2 = $90 ' Enable serial port & continuous receive
        TXSTA2 = $24 ' Enable transmit, BRGH = 1
        'CLROERR2 1 ' Clear overflow automatically
        SPBRG2 = 130 ' 9600 Baud @ 64MHz, -0,02%
        SPBRGH2 = 6
        BAUDCON2.3 = 1         ' Enable 16 bit baudrate generator
        

'------------------------------------------------------------------------------|
'-----------sent a sentence to gps, this is not working at the moment----------|
'------------------------------------------------------------------------------|
' When the GPS Module is POWERED ON, then the following sentenses are received. 

'          $PMTK011,MTKGPS*08
'          $PMTK010,001*2E
'          $PMTK010,002*2D   

pause 800 
HSEROUT2 ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration
pause 800

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
Pause 500

HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz
pause 100

It works the part of a baudrate change, when i send the command to the gps

Code:

HSEROUT2 ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration
pause 800

but i think the following it goes to GPS but for some reason is not set.

Code:

HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz
pause 100

**tumbleweed** · - 11th July 2018, 15:04

When you switch the baudrate you have to set both SPBRG2 and SPBRGH2.

Try:

Code:

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
SPBRGH2 = 1
Pause 500

**astanapane** · - 11th July 2018, 15:39

Originally Posted by tumbleweed

When you switch the baudrate you have to set both SPBRG2 and SPBRGH2.

Try:

Code:

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
SPBRGH2 = 1
Pause 500

It worked!!! I will post later on what i have done up to now. Maybe i need to set up a small indication when those commands are set. So i know that program is working up to that stage.

This is the code for changing the baudrate to GPS and the hz rate at 10Hz at the NMEA data.

Code:

'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 1 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|
        
        RCSTA = $90 ' Enable serial port & continuous receive
        TXSTA = $24 ' Enable transmit, BRGH = 1
        'CLROERR = 1 ' Clear overflow automatically
        SPBRG = 160 ' 38400 Baud @ 64MHz, -0,08%
        SPBRGH = 1
        BAUDCON.3 = 1         ' Enable 16 bit baudrate generator
        
'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | EUART 2 Configuration  | --------------------------|
'*                        |  --------------------- |                           |
'*-----------------------------------------------------------------------------|

        RCSTA2 = $90 ' Enable serial port & continuous receive
        TXSTA2 = $24 ' Enable transmit, BRGH = 1
        'CLROERR2 1 ' Clear overflow automatically
        SPBRG2 = 130 ' 9600 Baud @ 64MHz, -0,02%
        SPBRGH2 = 6
        BAUDCON2.3 = 1         ' Enable 16 bit baudrate generator
        

'------------------------------------------------------------------------------|
'-----------sent a sentence to gps, this is not working at the moment----------|
'------------------------------------------------------------------------------|
' When the GPS Module is POWERED ON, then the following sentenses are received. 

'          $PMTK011,MTKGPS*08
'          $PMTK010,001*2E
'          $PMTK010,002*2D   

pause 800 
HSEROUT2 ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration
pause 800

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
SPBRGH2 = 1
Pause 500

HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz
pause 100

**astanapane** · - 12th July 2018, 18:24

Dear all,

i need you help.

After removing all the DEFINEs and use only the following

Code:

'RCSTA2 = $90 ' Enable serial port & continuous receive
'TXSTA2 = $24 ' Enable transmit, BRGH = 1
'DEFINE HSER_CLROERR2 1 ' Clear overflow automatically
'SPBRG2 = 130 ' 9600 Baud @ 64MHz, -0,02%
'SPBRGH2 = 6
'BAUDCON2.3 = 1         ' Enable 16 bit baudrate generator

and for changing the baudrate and the frequency for the Second Serial,

Code:

pause 800 
HSEROUT2 ["$PMTK251,38400*27",13,10]      ' 38400 boundrate, check MTK manual configuration
pause 800

SPBRG2 = 160 ' 38400 Baud @ 64MHz, -0,08%
SPBRGH2 = 1
Pause 500

;HSEROUT2 ["$PMTK314,0,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0*29",13,10]
HSEROUT2  ["$PMTK314,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28",13,10]
pause 100

HSEROUT2 ["$PMTK220,100*2F",13,10]        ' 100(millisecond)=0.1(sec)-->1/0.1= 10Hz
pause 100

I found out that on SERIAL TERMINAL on the computer of course i see the data coming from the GPS but unfortunately when i connect an LCD to PIC using the first Serial, the data cannot be displayed.

It seems that when i use

Code:

HSERIN2[wait("$GPRMC")

the data cannot be read from the GPS to the RX of the PIC.

I tried to check if there is a problem with the LCD, but i can send text to the LCD.

I tried to check and use only the DEFINEs with 9600 because the default for the GPS is 9600 and it worked.

so when i do not use the defines, it looks like that RX port on the PIC doesnt work.

Could you please help?

Thread: GPS Project: PIC18F26K22 or PIC18F46K22

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