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cvargcal
Joined: 17 Feb 2015
Posts: 134
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| Error UART to 115200 baud |
 Posted: Thu Aug 13, 2020 11:00 pm |
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Hi,
Someone know why i cannot receive data to 115200?
I bought this module: https://www.aliexpress.com/item/32911363529.html If I use one converter TTL to USB, show without problem. But with this simple code show wrong character.
| Quote: | ID=10AÕ‚‰5HID=10PM03M
ID=10AÕ‚i5HID=10U‚iªCID=10U‚iªHID=10A5‚š5
ID=10U‚‰ªH@{FF} |
I can see only show the 2 first characters, the correct should be:
ID=10000107,TEP=+28.1¡æ,HUM=000.0%,S=00000001,V=3.38V,SN=026,RSSI=-027dBm{0D}{0A}
I tested all speed, the max where work is with 57600.
| Code: | #include <18F26k22.h>
#device PASS_STRINGS = IN_RAM
#device adc=10
#fuses NOPBADEN // PORTB pins are configured as digital I/O on RESET
#fuses BROWNOUT // Reset when brownout detected
#fuses NOHFOFST // High Frequency INTRC waits until stable before clocking CPU
#fuses NOWDT // No Watch Dog Timer
#fuses PUT // Power Up Timer
#fuses MCLR // Master Clear pin enabled
#fuses PROTECT // Code protected from reads
//#fuses PLLEN // HW PLL enabled 16MH* 4 =64M
#use delay(internal=64MHz)
// UARTs
//!/***************************************************************/
#use rs232(baud=115200,bits=8,parity=N,xmit=PIN_B6,rcv=PIN_B7,ERRORS,stream=uart2)
#use rs232(baud=9600,bits=8,parity=N,xmit=PIN_C6,rcv=PIN_C7,ERRORS,stream=uart1)
//!/***************************************************************/
#use standard_io(A)
#use standard_io(B)
#use standard_io(c)
#int_RDA
void RDA_isr1(void) {
}
#int_RDA2
void RDA_isr2(void) {
char bufferByte = getchar(uart2);
fputc(bufferByte,uart1);
}
void main(void){
fprintf(uart1,"test....");
enable_interrupts(global); // Habilita interrupciones
enable_interrupts(int_rda); // Habilita Interrupción RDA UART1
enable_interrupts(int_rda2); // Habilita Interrupción RDA UART2
delay_ms(500);
fprintf(uart1,"test....");
while(1);
} |
This PIC doesn't support high speed? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19510
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| Posted: Fri Aug 14, 2020 1:56 am |
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As a comment, use the UART name. Makes absolutely 'sure' you
use the hardware UART,
Also add a receive line to INT_RDA. Problem is you are enabling this
interrupt. If it triggers (UART1 RX is not pulled high), then the code at
this point will hang. Reason is that INT_RDA will be called, and then
can never exit, since you don't read the character. Means the interrupt
cannot be cleared.
Big problem though is the speed difference. Characters are arriving every
1/11520 second, but it takes a mSec to send a character at 9600bps
| Code: |
#include <18F26k22.h>
#device PASS_STRINGS = IN_RAM
#device adc=10
#fuses NOPBADEN // PORTB pins are configured as digital I/O on RESET
#fuses BROWNOUT // Reset when brownout detected
#fuses NOHFOFST // High Frequency INTRC waits until stable before clocking CPU
#fuses NOWDT // No Watch Dog Timer
#fuses PUT // Power Up Timer
#fuses MCLR // Master Clear pin enabled
#fuses PROTECT // Code protected from reads
//#fuses PLLEN // HW PLL enabled 16MH* 4 =64M
#use delay(internal=64MHz)
// UARTs
//!/***************************************************************/
#use rs232(baud=115200,bits=8,parity=N,UART2,ERRORS,stream=uart2)
#use rs232(baud=9600,bits=8,parity=N,UART1,ERRORS,stream=uart1, TRANSMIT_BUFFER=128)
//!/***************************************************************/
//Big issue here is the difference in speed.
//Adding the transmit_buffer option, will create an INT_TBE, and handle
//storing the data,
#use standard_io(A)
#use standard_io(B)
#use standard_io(c)
#int_RDA
void RDA_isr1(void) {
int dummy;
dummy=fgetc(uart1);
//unless the character is read, the interrupt cannot be cleared
//processor will then be hung.....
}
#int_RDA2
void RDA_isr2(void) {
char bufferByte = fgetc(uart2);
//Problem here is characters can arrive every 1/11000th second
//but the print below takes a mSec. After two characters the
//output buffer is full, so then things have to hang.....
fputc(bufferByte,uart1);
}
void main(void){
fprintf(uart1,"test....");
enable_interrupts(global); // Habilita interrupciones
enable_interrupts(int_rda); // Habilita Interrupción RDA UART1
enable_interrupts(int_rda2); // Habilita Interrupción RDA UART2
delay_ms(500);
fprintf(uart1,"test....");
while(TRUE) //if you use 'true', gets rid of compiler warning that
//condition is always true.
;
}
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temtronic
Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario
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| Posted: Fri Aug 14, 2020 4:51 am |
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just a comment...
If it still randomly fails after Mr. T's reply, consider using a real xtal/2 caps to replace the internal oscillator. Although the internal osc is pretty good (accurate) it may go 'out of spec' when cold or hot or may just be 'marginal'.
There's a reason why all the USBTTL and RTC modules have real xtals. To be accurate and precise you need an xtal.
Have to admit I use the 46K22 all the time without xtal/caps and they've been fine but in the beginning (3 decades ago) you NEEDED xtal/caps for reliable serial communications and timing. |
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cvargcal
Joined: 17 Feb 2015
Posts: 134
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| Posted: Fri Aug 14, 2020 10:55 am |
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You always show me the light!! thanks!!
I can use the same speed and now it show me exactly how do the TTL to USB... so I only changed the pins name by the uart name, and put the dummy in #int_RDA
| Code: |
// UARTs
//!/***************************************************************/
#use rs232(baud=115200,bits=8,parity=N,UART2,ERRORS,stream=uart2)
#use rs232(baud=115200,bits=8,parity=N,UART1,ERRORS,stream=uart1)
//!/***************************************************************/
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Always I had that question, why use the external crystal if less wire and less component make easy the things.
Once again, thanks.... now i can continue working in my code.
Last edited by cvargcal on Fri Aug 14, 2020 3:13 pm; edited 1 time in total |
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dyeatman
Joined: 06 Sep 2003
Posts: 1934
Location: Norman, OK
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| Posted: Fri Aug 14, 2020 10:56 am |
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Also, would not recommend using UART1 and UART2 as stream names since
they are reserved names for RS232 setup parameters. Might cause some
unwanted side effects.
_________________
Google and Forum Search are some of your best tools!!!! |
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temtronic
Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario
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| Posted: Fri Aug 14, 2020 11:50 am |
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followup comment....
stream names should reflect what they're used for
stream=GPSdevice
stream=PClink
The names tell you what the other device is. In the first case a GPS device is attached to the wires, in the second, a connection to a PC.
This can save a LOT of wasted time, when you 'misconnect' the UARTS to the wrong devices...
Jay |
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