LCD and HSEROUT do not mix well ?

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- 15th November 2008, 10:28
Johan

LCD and HSEROUT do not mix well ?

I tried to display decimal value to LCD, it works.

How to display the value to LCD while sending the value with HSEROUT ?
Everytime I enable the HSEROUT command , the LCD do not display anything , not even the "HELLO" at the beginning
If the HSEROUT line is disabled, the LCD works again

Please take a look at my code below. Thanks

Code:

'**************************************************************** '* Name : UNTITLED.BAS * '* Author : [select VIEW...EDITOR OPTIONS] * '* Notice : Copyright (c) 2008 [select VIEW...EDITOR OPTIONS] * '* : All Rights Reserved * '* Date : 14/11/2008 * '* Version : 1.0 * '* Notes : 16F88 20 Mhz * '* : PBP 2.50b MPASM * '**************************************************************** ASM __config _CONFIG1, _HS_OSC & _WDT_OFF & _LVP_OFF & _CP_ALL & _CCP1_RB3 __config _CONFIG2, _IESO_OFF & _FCMEN_OFF endasm define osc 20 define hser_rcsta 90h define hser_txsta 20h define hser_baud 9600 define hser_spbrg 25 DEFINE HSER_CLROERR 1 DEFINE LCD_DREG PORTB ' LCD data port DEFINE LCD_DBIT 0 ' LCD data starting bit DEFINE LCD_RSREG PORTA ' LCD register select port DEFINE LCD_RSBIT 3 ' LCD register select bit DEFINE LCD_EREG PORTA ' LCD enable port DEFINE LCD_EBIT 4 ' LCD enable bit DEFINE LCD_BITS 4 ' LCD data bus size DEFINE LCD_LINES 2 ' Number lines on LCD DEFINE LCD_COMMANDUS 2000 ' Command delay time in us DEFINE LCD_DATAUS 50 ' Data delay time in us CLEAR TRISA = %00000000 TRISB = %00000000 ANSEL = %00000000 value var byte lcdout $FE,1 start: LCDOUT $FE,1, " Hello" pause 50 for value = 1 to 255 LCDout $FE,$C0, dec value pause 50 ;hserout [0,dec value] ; IF THIS LINE IS ENABLED, LCD DOESN NOT DISPLAY ANYTHING pause 50 next value pause 5000 goto start
- 15th November 2008, 12:35
mat janssen

Try to put a pause of 1 sec. yust before your programm starts.
The display must be initialised. And that kosts time.
The instruction is faster then the display initialisation.
Between
value var byte
(here)
lcdout $FE,1

you put a pause ot 1 sec.
- 15th November 2008, 20:57
mister_e

If i remember correctly, lower bits of PORTB, ( PORTB.2 ) is also multiplexed with RX of the USART. And i don't remember if this PIC allow you to disable the RX part, so my guess would be...

Code:

for value = 1 to 255 RCSTA=0 ' Disable USART TRISB.2=0 pause 25 LCDout $FE,$C0, dec value pause 25 RCSTA=$90 ' enable USART pause 25 hserout [0,dec value] ; IF THIS LINE IS ENABLED, LCD DOESN NOT DISPLAY ANYTHING pause 50 next value

sure enough there's few unecessary delay up here... not sure if this will help and work at all using the above... Maybe a good situation to use SEROUT/SEROUT2/DEBUG?

PS: Make sure of your DEFINES, must all be in UPPERCASE, unless, it may not work.
- 15th November 2008, 23:19
Charles Linquis

Mister E is right, the DEFINES must be in upper-case, and are not checked by the compiler, which means there are no error messages if you don't enter them correctly - they just don't work.

Also, you are using PORTA.4 as your LCD ENABLE. You MUST put a pull-up on this port if you are going to use it as an output.
- 16th November 2008, 07:12
Archangel

Quote:

Originally Posted by mister_e

If i remember correctly, lower bits of PORTB, ( PORTB.2 ) is also multiplexed with RX of the USART. And i don't remember if this PIC allow you to disable the RX part, so my guess would be...

Code:

for value = 1 to 255 RCSTA=0 ' Disable USART TRISB.2=0 pause 25 LCDout $FE,$C0, dec value pause 25 RCSTA=$90 ' enable USART pause 25 hserout [0,dec value] ; IF THIS LINE IS ENABLED, LCD DOESN NOT DISPLAY ANYTHING pause 50 next value

sure enough there's few unecessary delay up here... not sure if this will help and work at all using the above... Maybe a good situation to use SEROUT/SEROUT2/DEBUG?

PS: Make sure of your DEFINES, must all be in UPPERCASE, unless, it may not work.

Hi Steve, A little time sharing going on in there, cool.
- 17th November 2008, 11:20
Johan

Thank you for your help :)
I modifies as Steve's suggestion, it works now

Actually I do not require the RX part, is there any way permanently disable the RX part ( to save 2x pause 25 ) ?
- 17th November 2008, 16:38
mister_e

Not sure you require them anyways... seems there's no way to use only the Transmitter section. So, or you change HSEROUT to DEBUG, or you add the above in your code.

Probably I would use the DEBUG route myself.