PIC HSERIN problem

**Archangel** · - 16th July 2008, 06:06

I cannot point to it, but I am betting there is an interrupt flag that gets set the first go around that you need to clear in code.

**Bruce** · - 16th July 2008, 23:42

It may help by adding DEFINE HSER_CLROERR 1 to your USART init section.

**shaiqbashir** · - 17th July 2008, 03:00

ok guys!

so i have studied a few threads here and made the following modifications in the SPI master program. but again the same problem is occuring. In the first iteration, the program runs very fine, but when it comes to hserin the second time, the program halts and no data is hserin in the pic.

plz help me , this is my final year project, and due to this the whole project is getting affected.

Code:

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2008 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 7/5/2008                                          *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
Include "Modedefs.Bas"

DEFINE HSER_RCSTA 90h 
DEFINE HSER_TXSTA 24h 
DEFINE HSER_BAUD 9600
DEFINE HSER_SPBRG 25
DEFINE HSER_CLROERR 1 


define OSC 4

' Set LCD Data port
DEFINE LCD_DREG PORTD
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 0
' Set LCD Register Select port
DEFINE LCD_RSREG PORTC
' Set LCD Register Select bit
DEFINE LCD_RSBIT 0
' Set LCD Enable port
DEFINE LCD_EREG PORTC
' Set LCD Enable bit
DEFINE LCD_EBIT 1
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 8
' Set number of lines on LCD
DEFINE LCD_LINES 2
' Set command delay time in us
DEFINE LCD_COMMANDUS 2000
' Set data delay time in us
DEFINE LCD_DATAUS 50

SSPEN	VAR		SSPCON1.5	'SSP Enable bit
CKP		VAR		SSPCON1.4	'Clock Polarity Select
SMP		VAR		SSPSTAT.7	'Data input sample phase
CKE		VAR		SSPSTAT.6	'Clock Edge Select bit
SSPIF	VAR		PIR1.3		'SPI interrupt flag
OERR   var     RCSTA.1
CREN    var     RCSTA.4
RCIF    VAR     PIR1.5
RCIE    var     PIE1.5

i		VAR		BYTE
j var byte	
as var byte[5]	
com		VAR		byte[2]
sen     var     byte[6]	
teds1   var     byte[10]
teds2   var     byte[10]
teds3   var     byte[10]
op1     var     byte
teds_out var byte[25]
sen0    var     byte[10]
sen_all var     byte[20]
a var byte[10]
DUM VAR BYTE

TRISC = %10010000	'set PORTC I/O

INTCON=%11000000
PIE1.5=1

		
SSPEN = 1			'enable SPI pins
CKP = 0				'clock idle low
CKE = 0				'transmit on idle to active transition
SSPIF = 0			'clear buffer full status
SMP = 0				'sample in middle of data
SSPCON1.0 =  0
SSPCON1.1 =  0
SSPCON1.2 =  0
SSPCON1.3 =	 0

main:
RCIE=1
pause 100
if RCIF=1 then in 
hserout["initialized....",13,10]
pause 10
goto main

in:
dum=RCREG
pause 50
hserout["you entered",dec dum,13,10]
pause 100
goto loop


loop:
SSPEN=1
pause 100
for j=0 to 10
high portB.0
pause 25
low portB.0
pause 25
		GoSub getdata		'initiate conversion and receive data
        LCDOut $fe, 1, STR a\5, DEC a[5]	'display received string
		Pause 100
		hserout [dec a[4]," ",dec a[5]," ",dec a[6],13,10]
		pause 100
		next j
        pause 100
        goto check
		

getdata:					
		
		SSPBUF = "?"					'send ? to start conversion
		GoSub letclear					'wait for buffer to clear
		IF SSPBUF<>"!" Then getdata		'wait for reply (!)

		For i = 0 to 5		'loop for 6 characters
			SSPBUF = 0		'write to SSPBUF to start clock
			GoSub letclear	'wait for receipt
			a[i] = SSPBUF	'store received character in array
		Next i				'get next character

		Return
		

letclear:

		IF SSPIF = 0 Then letclear	'wait for SPI interupt flag
		PauseUs 25					'25uS fudge factor
		SSPIF = 0					'reset flag
		Return	
        
check:
RCIE=0
WHILE RCIF=1
DUM=RCREG
hserout["find",13,10]
pause 100
CREN=0
pause 25
WEND

goto main

**Archangel** · - 17th July 2008, 07:13

Seems like you need to follow CREN=0 with CREN=1 to reenable continuous receive

skimask · - 17th July 2008, 14:19

Originally Posted by Joe S.

Seems like you need to follow CREN=0 with CREN=1 to reenable continuous receive

DEFINE HSER_CLROERR 1...PBP handles that 'internally.

skimask · - 17th July 2008, 14:20

Originally Posted by shaiqbashir

so i have studied a few threads here and made the following modifications in the SPI master program. but again the same problem is occuring. In the first iteration, the program runs very fine, but when it comes to hserin the second time, the program halts and no data is hserin in the pic.

Which of the 0 HSERIN statements in the above code would that be?

plz help me , this is my final year project, and due to this the whole project is getting affected.

**shaiqbashir** · - 18th July 2008, 01:25

actually my code is something like this

Code:

Include "Modedefs.Bas"

DEFINE HSER_RCSTA 90h 
DEFINE HSER_TXSTA 24h 
DEFINE HSER_BAUD 9600
DEFINE HSER_SPBRG 25
DEFINE HSER_CLROERR 1 


define OSC 4

' Set LCD Data port
DEFINE LCD_DREG PORTD
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT 0
' Set LCD Register Select port
DEFINE LCD_RSREG PORTC
' Set LCD Register Select bit
DEFINE LCD_RSBIT 0
' Set LCD Enable port
DEFINE LCD_EREG PORTC
' Set LCD Enable bit
DEFINE LCD_EBIT 1
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS 8
' Set number of lines on LCD
DEFINE LCD_LINES 2
' Set command delay time in us
DEFINE LCD_COMMANDUS 2000
' Set data delay time in us
DEFINE LCD_DATAUS 50

SSPEN	VAR		SSPCON1.5	'SSP Enable bit
CKP		VAR		SSPCON1.4	'Clock Polarity Select
SMP		VAR		SSPSTAT.7	'Data input sample phase
CKE		VAR		SSPSTAT.6	'Clock Edge Select bit
SSPIF	VAR		PIR1.3		'SPI interrupt flag
OERR   var     RCSTA.1
CREN    var     RCSTA.4
RCIF    VAR     PIR1.5
RCIE    var     PIE1.5

i		VAR		BYTE
j var byte	
as var byte[5]	
com		VAR		byte[2]
sen     var     byte[6]	
teds1   var     byte[10]
teds2   var     byte[10]
teds3   var     byte[10]
op1     var     byte
teds_out var byte[25]
sen0    var     byte[10]
sen_all var     byte[20]
a var byte[10]
DUM VAR BYTE

TRISC = %10010000	'set PORTC I/O

INTCON=%11000000
PIE1.5=1

		
SSPEN = 1			'enable SPI pins
CKP = 0				'clock idle low
CKE = 0				'transmit on idle to active transition
SSPIF = 0			'clear buffer full status
SMP = 0				'sample in middle of data
SSPCON1.0 =  0
SSPCON1.1 =  0
SSPCON1.2 =  0
SSPCON1.3 =	 0

main:
RCIE=1
pause 100
if RCIF=1 then in 
hserout["initialized....",13,10]
pause 10
goto main

in:
hserin[wait("x"),str com\2]
pause 50
hserout["you entered",str com\3,13,10]
pause 100
goto loop


loop:
SSPEN=1
pause 100
for j=0 to 10
high portB.0
pause 25
low portB.0
pause 25
		GoSub getdata		'initiate conversion and receive data
        LCDOut $fe, 1, STR a\5, DEC a[5]	'display received string
		Pause 100
		hserout [dec a[4]," ",dec a[5]," ",dec a[6],13,10]
		pause 100
		next j
        pause 100
        goto check
		

getdata:					
		
		SSPBUF = "?"					'send ? to start conversion
		GoSub letclear					'wait for buffer to clear
		IF SSPBUF<>"!" Then getdata		'wait for reply (!)

		For i = 0 to 5		'loop for 6 characters
			SSPBUF = 0		'write to SSPBUF to start clock
			GoSub letclear	'wait for receipt
			a[i] = SSPBUF	'store received character in array
		Next i				'get next character

		Return
		

letclear:

		IF SSPIF = 0 Then letclear	'wait for SPI interupt flag
		PauseUs 25					'25uS fudge factor
		SSPIF = 0					'reset flag
		Return	
        
check:
RCIE=0
WHILE RCIF=1
DUM=RCREG
WEND

CREN=0 
pause 25
CREN=1
pause 25
goto main

What basically is a happening that the first HSERIN instrunction which is
HSERIN[wait("x"),str com\2] is executing only once, that is when i turn on the power. the pIC successfuly takes 2 characters as an input after "x" and displays sensors data 10 times which it has acquired from SPI slave through SPI communications. and then when it comes to HSERIN[wait("x"),str com\2] again, it doesnt execute at all, and the PIC seems to be halted.

One observation that i got is this that when i donot use SPI in the above program, im able to use HSERIn again and again. So i think that the problem is somewhere in using SPI. PLease help me dear

**Dave** · - 18th July 2008, 12:25

shaiqbashir, Where is your interrupt routine? You are setting up the interrupts but only looking at the interrupt input flags. There is no need to setup the global interrupt bits as once again all you are doing is (polling) looking at the input flag bits..

Dave Purola,
N8NTA

**shaiqbashir** · - 20th July 2008, 02:04

ok i will disable global interrupts and will check it. But interrupt is not a problem here. The first time it executes very perfectly, it is the second time that is creating a huge problem. Second time, on hserin statement, the PIC hangs.
kindly help

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