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GPS NMEA antenna aiming tracker.
- Thread starter camerart
- Start date
Not sure about your simulator, but the NMEA serial data from the GPS module connects to the RX input of the PIC USART. And the two grounds also need to be connected.
In the PIC (and in the simulator I guess) you need to turn the USART module on and configure its baudrate. The PIC datasheet has a chapter that explains all that in step by step form.
The_RB,Not sure about your simulator, but the NMEA serial data from the GPS module connects to the RX input of the PIC USART. And the two grounds also need to be connected.
In the PIC (and in the simulator I guess) you need to turn the USART module on and configure its baudrate. The PIC datasheet has a chapter that explains all that in step by step form.
I misled you! Sorry. I meant in the Oshonsoft simulator, for testing, I had to cut and paste an example NMEA sentence, into the USART I think, then in simulation print the data on the simulation LCD. At the moment the SIM reports 'UART receiver is not enabled'
Camerart.
hi C,
Try this.
Its a Copy of a post I made for you on another forum site.
NOTE : I have terminated the string with a '?' character as a temporary substitute for the LF [ saves using the send hex]
Copy the string shown at the Top of the program and Paste it into the Oshonsoft Tool Hardware UART Send String Box,
DONT include the Rem at the start.
'COPY and PASTE this string. '$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47?
I have left some of your Dim's statements in, needs a tidy up.
It works as a Demo.
Try this.
Its a Copy of a post I made for you on another forum site.
NOTE : I have terminated the string with a '?' character as a temporary substitute for the LF [ saves using the send hex]
Copy the string shown at the Top of the program and Paste it into the Oshonsoft Tool Hardware UART Send String Box,
DONT include the Rem at the start.
'COPY and PASTE this string. '$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47?
I have left some of your Dim's statements in, needs a tidy up.
It works as a Demo.
Rich (BB code):
Code (text):
'software uart receives data stream at 9600 baud And when code gga is detected we capture 42 bytes
'in array a(42) then send these to the PC via hardware UART at 9600 baud
'COPY and PASTE this string.
'$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47?
Define SIMULATION_WAITMS_VALUE = 1
Dim chr As Byte
Dim rxi As Byte
Dim txi As Byte
Dim start_code(2) As Byte 'enables scan of the last 3 characters received
Dim str1(42) As Byte 'save the data stream we need in here
Dim i As Byte
Dim j As Byte
Dim gga As Byte
Dim data As Byte
Dim latdeg As Byte
Dim latmin As Byte
Dim londeg As Byte
Dim lonmin As Byte
'> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >.
Define CONF_WORD = 0x3f41 'XTL
Define CLOCK_FREQUENCY = 4 'Changed from 12
AllDigital
'Define osc 4
CMCON = 7
OPTION_REG.7 = 0 'Enable Pull-Up's
Dim led_a2 As Bit 'PORTA.2 'flash per second
Define LCD_DREG = PORTB 'Port for LCD Data
Define LCD_DBIT = 4 'Use upper 4 bits of Port
Define LCD_RSREG = PORTA 'Port for RegisterSelect (RS) bit
Define LCD_RSBIT = 2 'Port Pin for RS bit (pin9)
Define LCD_EREG = PORTA 'Port for Enable (E) bit
Define LCD_EBIT = 4 'Port Pin for E bit (pin7)
Define LCD_BITS = 4 'Using 4-bit bus
Define LCD_LINES = 4 'Using 2 line Display
Define LCD_CHARS = 16 'ADDED
Define LCD_COMMANDUS = 2000 'Command Delay (uS)
Define LCD_DATAUS = 50 'Data Delay (uS)
'Define osc 4
CMCON = 7
OPTION_REG.7 = 0 'Enable Pull-Up's
TRISA = %00000000
TRISB = %01000000
'$GGA 1234
Lcdinit
Hseropen 9600
INTCON.GIE = 1
INTCON.PEIE = 1
PIE1.RCIE = 1
Hserout "Ready - await $", CrLf, CrLf
main:
Goto main
End
On Interrupt
Save System
PIR1.RCIF = 0
Hserin chr
If chr = "$" Then ' test for string start
rxi = 0
Endif
str1(rxi) = chr
rxi = rxi + 1
If chr = "?" Then 'test for temporary LF code
For txi = 0 To rxi
Hserout str1(txi)
If str1(txi) = "," Then Hserout CrLf ' a demo on how to break the string into chunks.!
Next txi
Endif
ResumeAttachments
Hi E,
You have answered my question, but the program you posted was for the earlier PIC 16F886, I've since updated to 18F4520. I tried again with the program that I just posted, and it shows incorrect data, but I haven't added DIMs yet. I might be able to get it going, thanks.
C
Hi Eric,
Please see #130.
EDIT: Found a few errors so here it is again with less errors
When I paste the $sentence into UART, it reports:'incorrect input'
Cheers, Camerart.
Last edited:
hi C.
The copper cuts and connections around the 7805 and crystal are a real mess.
It look as though you could have +Vinp to the xtal circuit as well as the 7805. Check with a voltmeter the Xtal pins 13 and 14 of the PIC
Why all the resistors around the crystal.?
Also, there is no decoupling at all on the +5V supply, either In or Out of the 7805.
You must have decoupling capacitors on these regulator supplies.
Sorry to be so blunt.
E
The copper cuts and connections around the 7805 and crystal are a real mess.
It look as though you could have +Vinp to the xtal circuit as well as the 7805. Check with a voltmeter the Xtal pins 13 and 14 of the PIC
Why all the resistors around the crystal.?
Also, there is no decoupling at all on the +5V supply, either In or Out of the 7805.
You must have decoupling capacitors on these regulator supplies.
Sorry to be so blunt.
E
Attachments
Hi Eric,
I added the resistors after suggestions to get the crystal working. It has got messy, because I've swapped every thing, a few times. Probably best if I start again.
Thanks, C.
hi,
If you rebuild, mount the 7805 away from the PIC, use a 100nF and 47uF on both the input and out of the 7805 , close to the 7805.
Dedicate a copper track to +5V and one for the 0V
Link the +5V and 0V to the PIC power pins,
Add a 100nF on the back of the PCB, across the +5V and 0V, close to the PIC power pins.
Use only 15pF or 22pF from each 20Mhz crystal pin to 0V. [ leave space to add a 1meg resistor later on, IF required]
If you plan to use the /MCLR pin, place a 10K from pin#1 to +5V.
Dont connect the Keypad or LCD at this time, add a 270R and a LED from a PIC output pin.
Write a test program that only flashes the LED on/off at say 1 second rate.
[ do not enable Interrupts]
Once the LED flashes at say 1 second you know the Xtal section is debugged.!
Then add the LCD, again write a LCD test program that just displays Hello.!
Next add the Keypad, with a keypad test program.
If you debug to that point , then I would suggest you write a UART test program.
Eric
If you rebuild, mount the 7805 away from the PIC, use a 100nF and 47uF on both the input and out of the 7805 , close to the 7805.
Dedicate a copper track to +5V and one for the 0V
Link the +5V and 0V to the PIC power pins,
Add a 100nF on the back of the PCB, across the +5V and 0V, close to the PIC power pins.
Use only 15pF or 22pF from each 20Mhz crystal pin to 0V. [ leave space to add a 1meg resistor later on, IF required]
If you plan to use the /MCLR pin, place a 10K from pin#1 to +5V.
Dont connect the Keypad or LCD at this time, add a 270R and a LED from a PIC output pin.
Write a test program that only flashes the LED on/off at say 1 second rate.
[ do not enable Interrupts]
Once the LED flashes at say 1 second you know the Xtal section is debugged.!
Then add the LCD, again write a LCD test program that just displays Hello.!
Next add the Keypad, with a keypad test program.
If you debug to that point , then I would suggest you write a UART test program.
Eric
Thanks Eric, The sim still reports 'incorrect input' ($GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47)
I'm wondering if the UART is not for this PIC, in the 18F4520 data sheet I can only find USART.
Camerart.
