GPS Project: PIC18F26K22 or PIC18F46K22

[astanapane]

Dear all,

i have a question it maybe answered in lots of different threads.
http://www.picbasic.co.uk/forum/showthread.php?t=10389

http://www.picbasic.co.uk/forum/showthread.php?t=10265

QUESTION: Can i have different baudrates on the 2 EUARTs? How could i change baudrate during start up in one of the EUART port?

Have in mind that i use both of the EUARTs. One for the Display and one for the GPS.

The GPS has a firmware with the following configuration:

Baudrate: 9600 default
Refresh rate: 1hz

On the code i have configured the EUART for 38400, because i set the GPS externally with serial terminal at 38400. But GPS keeps the configs only if a backup battery is presented.

So i came up with this problem.

I need to send the following command first to SET the BAURATE at 38400, but with the EUART at 9600, because at that stage the GPS communicate only at 9600.

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

Then GPS as i tested i connected successfully, at 38400, but the following command cannot be sent before i change on the fly the EUART at 38400.

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

From the links above, i checked the way you are setting the new baudrate, and tried to do it as well but didnt really worked.

[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.

[astanapane]

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.

'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | 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.

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.

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.

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

[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

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

is only half the job

[astanapane]

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

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]

Dear all,

i did the following....

'*-----------------------------------------------------------------------------|
'*                        |  --------------------- |                           |
'*----------------------- | 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

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.

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

[tumbleweed]

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

Try:

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