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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| RS232 async 16F887 vs 18f4520 |
 Posted: Tue Aug 04, 2009 6:02 pm |
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Using combined PCM PCH ver 4.085
( a search for PCH serial problem returns 1300+ hits - )
RS232 converting to 18f4520 is way off of speed.
The 16f887 program below works perfectly.
BUT
the 18f4520 converted versions only produces a short burst of VERY hi baud rate data - that evaluates to a single 0xfd - 0xFF when received at 38400.
I have set the TRIS in C and the SPEN bit per the data sheet but something fundamental is still wrong and I am just not seeing it.
Below WORKS fine
| Code: |
#include <16f887.h>
// 18f #include <18f4520.h>
#include <stdlib.h>
#FUSES NOPROTECT,NOMCLR,INTRC_IO,NOWDT,NODEBUG,NOLVP,NOIESO,
#fuses NOFCMEN,PUT,NOWRT,NOFCMEN,NOBROWNOUT,
// above old '16f887 fuses new 18f fuses added below
// 18f #fuses CCP2C1,NOPBADEN,NOLPT1OSC,
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
#use fast_io(D)
#use fast_io(E)
#use delay( clock=8000000,INTERNAL ) // clock 8 mhz int
#use rs232(baud=38400, xmit=PIN_C6, rcv=PIN_C7, ERRORS )
int NumberOfArguments;
char ArgumentString[12]; // used to be 10
void minorVER(void){
printf(__DATE__); printf(__TIME__); printf( " Ver FX\r"); //
}
void greetmsg(void){ printf ( "ECIS MH2 \r" ); //output message
}
void baddie(void){ printf( "-\r"); } // bad arg problem
void goodie(){ printf( "!\r"); } // bad arg problem
//***********************************
void InitHDW ( void ) {
//***********************************
setup_oscillator ( OSC_8MHZ );
output_a (0); output_b (0); output_c (0); output_d (0); output_e (0xFF);
set_tris_a (0); // all output
set_tris_b (0); // all output
set_tris_c (3); // 00000011 low = C0,C1 are inputs
set_tris_d (0xFF); // all input
set_tris_E ( 0xE9 ); // 1110 1001 with Parallel Slave Port mode off
setup_adc_ports( NO_ANALOGS );
setup_adc( ADC_OFF );
setup_timer_0( RTCC_DIV_128 ); // set for rollovers 10 ms 8 mhz
}
void PodType ( void ) {
printf ( "podis3\r" ); // send back pod well count
}
int ParseCommand ( char NewChar ) {
int Command; int i;
static char ReceiveBuffer[10]; // MAX CMD LEN =10 actuall 1 + 6+1
static int BufferIndex = 0;
NumberOfArguments = 0;
ReceiveBuffer[BufferIndex++] = NewChar;
// Error if command is too long
if ( BufferIndex == 11 ) {
BufferIndex = 0;
return ( 0 ); // BAD value we overflowed
}
// CR= command is complete
// CR vs LF so check for them both
// ignore 0 length commands because probably just a CR/LF combination
if ( (NewChar == '\r') || (NewChar == '\n') ) {
// Ignore it
if ( BufferIndex == 1 ) {
BufferIndex = 0;
Return 0;
}
Command = ReceiveBuffer[0] ;
ReceiveBuffer[BufferIndex] = 0;
if ( BufferIndex == 2 ) {
NumberOfArguments = 0;
} else {
for (i=0;i<11;i++){
ArgumentString[i] = ReceiveBuffer[i+1];
}
NumberOfArguments = 1;
}
BufferIndex = 0;
return Command;
}
// If here then still just building the command
return 0;
}
void ProcessCommand ( int Command ) {
switch ( Command ) {
case '?': PodType(); break; // P!
case '-': minorVer(); break; //P!
case '*': greetmsg(); break; //P!
default : baddie();
}
}
//
//******
main() {
//******
char NewChar;
int Command;
InitHDW();
greetmsg();
while (1) {
while ( kbhit() ) { // chgd from IF to clean QUE
// There is a character so read it
NewChar = getc();
// Add the new character to the buffered command
Command = ParseCommand ( NewChar );
switch ( Command ) {
case 0: // A complete command has not yet been received - do nothing
break;
default:
// A complete (but not necessarily valid) command received - process it
ProcessCommand ( Command );
break;
}
}
}
}
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Below rets ONE obviously WAY overbaud burst as seen on scope
| Code: |
#include <18f4520.h>
#include <stdlib.h>
#FUSES NOPROTECT,NOMCLR,INTRC_IO,NOWDT,NODEBUG,NOLVP,NOIESO,
#fuses NOFCMEN,PUT,NOWRT,NOFCMEN,NOBROWNOUT,
// above old '16f887 fuses new 18f fuses added below
#fuses CCP2C1,NOPBADEN,NOLPT1OSC,noxinst,
#use delay( clock=8000000,INTERNAL ) // clock 8 mhz int
#use rs232(baud=38400, xmit=PIN_C6, rcv=PIN_C7, ERRORS )
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
#use fast_io(D)
#use fast_io(E)
#bit spen = 0xFAB.7
int NumberOfArguments;
char ArgumentString[12]; // used to be 10
void minorVER(void){
printf(__DATE__); printf(__TIME__); printf( " Ver FX\r"); //
}
void greetmsg(void){ printf ( "ECIS MH2 \r" ); //output message
}
void baddie(void){ printf( "-\r"); } // bad arg problem
void goodie(){ printf( "!\r"); } // bad arg problem
//***********************************
void InitHDW ( void ) {
//***********************************
setup_oscillator ( OSC_8MHZ |OSC_INTRC|OSC_PLL_OFF );
output_a (0); output_b (0); output_c (0); output_d (0); output_e (0xFF);
set_tris_a (0); // all output
set_tris_b (0); // all output
// 18f TRIS bit 6,7 chgs
set_tris_c (0b11000011); // 00000011 low = C0,C1 are inputs
set_tris_d (0xFF); // all input
set_tris_E ( 0xE9 ); // 1110 1001 with Parallel Slave Port mode off
spen=1; // 18f SPEN change
setup_adc_ports( NO_ANALOGS );
setup_adc( ADC_OFF );
setup_timer_0( RTCC_DIV_128 ); // set for rollovers 10 ms 8 mhz
}
void PodType ( void ) {
printf ( "podis3\r" ); // send back pod well count
}
int ParseCommand ( char NewChar ) {
int Command; int i;
static char ReceiveBuffer[10]; // MAX CMD LEN =10 actuall 1 + 6+1
static int BufferIndex = 0;
NumberOfArguments = 0;
ReceiveBuffer[BufferIndex++] = NewChar;
// Error if command is too long
if ( BufferIndex == 11 ) {
BufferIndex = 0;
return ( 0 ); // BAD value we overflowed
}
// CR= command is complete CR vs LF so check for them both
// ignore 0 length commands because probably just a CR/LF combination
if ( (NewChar == '\r') || (NewChar == '\n') ) { // Ignore it
if ( BufferIndex == 1 ) {
BufferIndex = 0;
Return 0;
}
Command = ReceiveBuffer[0] ;
ReceiveBuffer[BufferIndex] = 0;
if ( BufferIndex == 2 ) {
NumberOfArguments = 0;
} else {
for (i=0;i<11;i++){
ArgumentString[i] = ReceiveBuffer[i+1];
}
NumberOfArguments = 1;
}
BufferIndex = 0;
return Command;
} // If here then still just building the command
return 0;
}
void ProcessCommand ( int Command ) {
switch ( Command ) {
case '?': PodType(); break; // P!
case '-': minorVer(); break; //P!
case '*': greetmsg(); break; //P!
default : baddie();
}
}
//
//******
main() {
//******
char NewChar;
int Command;
InitHDW();
greetmsg();
while (1) {
while ( kbhit() ) { // chgd from IF to clean QUE
// There is a character so read it
NewChar = getc();
// Add the new character to the buffered command
Command = ParseCommand ( NewChar );
switch ( Command ) {
case 0: // A complete command has not yet been received - do nothing
break;
default:
// A complete (but not necessarily valid) command received - process it
ProcessCommand ( Command );
break;
}
}
}
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 04, 2009 6:37 pm |
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Clues:
What additional feature does Timer0 have in the 18F4520, that it doesn't
have in the 16F887 ? What is the compiler's default setting for that
feature in the 18F4520 ? How can you configure Timer0 to be compatible
with the 16F887 ? What is to be found in the 18F4520.h file in the Timer0
section ? |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| excellent asnwer |
| Posted: Tue Aug 04, 2009 6:54 pm |
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working on it
BUT the first thing i tried was using the 18f4620 instead
no other change except the #device line
and bang it WORKS for the F8620
SO i am
decoding the default state of timer0 from the .H file is proving more of a challenge than i thought
16 bit ? WDT on ? even with the fuse set NO ?
no other obvious interaction with EUASART system / master clock timing but back to the spec sheet i go |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Tue Aug 04, 2009 7:15 pm |
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holy heck !!!
i thought the #fuse that i set
took care of the whole issue
meaning i did not have to exlicitly disable the darned 'feature' thingie !!!
since i never use that bit of kit
i always assumed the the NOWDT fuse handled the problem
got it now
BUT how come i DON'T have to disable the same item on the 18f4620 ?????? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 04, 2009 7:42 pm |
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Maybe I misunderstood your problem. I was literally just about to leave
the office for the day. I saw a problem in the configuration of Timer0
and I jumped on it. (the 18F part defaults to a 16-bit Timer. The 16F
is 8-bit only). |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Tue Aug 04, 2009 7:51 pm |
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naw -
the 4620 worked with NO other changes except
TRIS_C bits 6,7 and SPEN - did not matter if i was using deflt 16 bit or 8 bit timer0
then for the 4520 i added the RTCC_8bit to my timer0 setup but still no fix
//** 4520
problem finally went away when i
added setuP_wdt( no_wdt); EARLY in my INIT function
even tho
i had done the NO_WDT fuse for the same part
very very weird
any ideas ?? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 04, 2009 7:53 pm |
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Post your compiler version. It's given at the top of the .LST file.
It will be like this: 4.096 (or whatever it is). |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Tue Aug 04, 2009 7:56 pm |
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i did - and always do
it was the FIRST line of my original post
and still is 4.085 ;-)) |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| further amplifying |
| Posted: Tue Aug 04, 2009 8:15 pm |
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for sure - the magic change was disabling the WDT - then chip worked
- serial came on all fine - no other change did bupkis
other notes - i did NOT assert WDT32768 -
nor BORV20 - yet there it is
from the .LST for the 4520
Word 1: 0800 NOIESO NOFCMEN INTRC_IO
Word 2: 1E18 NOBROWNOUT NOWDT BORV20 PUT WDT32768
Word 3: 0100 NOPBADEN CCP2C1 NOLPT1OSC NOMCLR RESERVED
Word 4: 0081 STVREN NODEBUG NOLVP NOXINST RESERVED
Word 5: C00F NOPROTECT NOCPD NOCPB
Word 6: E00F NOWRT NOWRTD NOWRTC NOWRTB
Word 7: 400F NOEBTR NOEBTRB
word 2 does NOT look exactly right to me but i could be wrong
i think NOwdt is asserted properly but the BORV20 and WDT32768 are not my doing
anybody make better sense of the fuse mess ?
- IF WDTEN is actually 0
then the doc says that SWDTEN now controls WDT operation
SWDTEN is in WDTCON and is the ONLY bit in the register
and sez IT defaults to 0 on power up per doc
am i misreading it ?
is it me - or the compiler ? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 04, 2009 8:29 pm |
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If you have a baud rate problem, my advice is to strip it down and
see if you still have the problem:
| Code: | #include <18f4520.h>
#FUSES NOPROTECT,NOMCLR,INTRC_IO,NOWDT,NODEBUG,NOLVP,NOIESO,
#fuses NOFCMEN,PUT,NOWRT,NOFCMEN,NOBROWNOUT,
#fuses CCP2C1,NOPBADEN,NOLPT1OSC,noxinst
#use delay( clock=8000000,INTERNAL) // clock 8 mhz int
#use rs232(baud=38400, xmit=PIN_C6, rcv=PIN_C7, ERRORS )
//====================================
void main()
{
printf("Hello World\n\r");
while(1);
} |
If you do, then change the main() code to this and look at the signal
with an oscilloscope:
| Code: | void main()
{
while(1)
{
putc(0x55);
}
} |
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