LCD and Serial Communication

[H2TECH]

After making the leap to PC-PIC serial communication, I have encountered one problem. Using an adapted code from the Val() function example, this code runs well. It sends serial messages and receives them without a flaw. However, I have adapted the code to also print messages on an LCD display. Instead, the LCD screen does not display anything. I have confidence the LCD module fully works, but there must be a conflict between the USART and the LCD program. I believe I might have stumbled upon someone with the same problem, but that was months ago. The code is below (Be aware I have "'" before the #define lines):

'#chip 16f628a, 4
'#config osc = int

'Set up hardware serial connection
'#define USART_BAUD_RATE 9600
'#define USART_BLOCKING
'#define LCD_IO 4
'#define LCD_DB7 PORTA.1
'#define LCD_DB6 PORTA.0
'#define LCD_DB5 PORTA.7
'#define LCD_DB4 PORTA.6
'#define LCD_RS PORTB.4
'#define LCD_RW PORTB.5
'#define LCD_Enable PORTB.6

'Variable for output level
Dim OutputLevel As Word

'Variables for received bytes
Dim DataIn As String
DataInCount = 0

cls
print "Ready"
hserprint "Serial Test"
hsersend 13
hsersend 10

Do
'Get serial byte
Wait Until USARTHasData
HSerReceive InByte

'Process latest byte
'Enter key?
If InByte = 13 Then
    'Convert output level to numeric variable
    OutputLevel = Val(DataIn)

    cls
    print outputlevel

    'Clear output buffer for next command
    DataIn = ""
    DataInCount = 0
End If

'Number?
If InByte >= 48 and InByte <= 57 Then
    'Add to end of DataIn string        
    DataInCount += 1
    DataIn(DataInCount) = InByte
    DataIn(0) = DataInCount
End If

Loop

It is straight forward and very similar to the original example and copied from. Is there a conflict between the USART and LCD code?

[Saša]

Hello, a post a code that works for me. I can display data i.e text (commands) and values (numeric). If I want to set pwm to 128 i simply send command and integer to PIC and then display on LCD what PIC receives from rs232 and then to execute a command received.
Hope it helps. Sorry for bad english.

Code used is simple and derived from help file.

'#chip 16F887, 8
'#config osc = Int

'#define USART_BAUD_RATE 9600
'#define LCD_IO 4
'#define LCD_NO_RW
'#define LCD_DB4 PORTB.0
'#define LCD_DB5 PORTB.1
'#define LCD_DB6 PORTB.2
'#define LCD_DB7 PORTB.3
'#define LCD_RS PORTB.4
'#define LCD_Enable PORTB.5

'#define USART_BAUD_RATE 9600
'#define USART_BLOCKING 'This is important instruction

'Set pin directions for USART and PWM
' I use RS232 and PWM to test it
dir PortC.7 in
Dir PortC.6 Out
Dir PortC.2 Out

'Variable for output level
Dim OutLevel As Word 'This will be value
Dim Rijec as string 'This will be command

'Variables for received bytes
Dim DataIn As String
Dim ZnakIn as string
ZnakCount=0
DataInCount = 0

Main:
Do
'Get serial byte
'Wait Until USARTHasData
HSerReceive InByte
wait 10 ms
HSerSend inbyte
'Process latest byte
'Enter key?
If InByte = 13 Then
cls
'Convert output level to numeric variable
Outlevel = Val(DataIn)
Rijec=znakin
lOCATE 0,0 : PRINT "Naredba: " ' This stands for command
LOCATE 0,10 : PRINT RIJEC
Locate 1,0 : Print "Iznos: " ' This stands for value
Locate 1,10 : Print OutLevel
'Output
if rijec="PWM" then ' If you send from terminal "PWM"
HPWM 1, 1, Outlevel 'PWM will be set to value given
else
Locate 3,0 :Print "Nedefinirano!" ' No command defined!"
end if
' In terminal you may send in one line PWM255 to set PWM output to full
' or PWM128 or any other value you wish
' Also you may define your own commands, i.e. Left, right, On, Off and so on...

'Clear output buffer for next command
DataIn = ""
DataInCount = 0
znakin=""
znakcount=0
End If
'Number?
If InByte >= 48 and InByte <= 57 Then
'Add to end of DataIn string
DataInCount += 1
DataIn(DataInCount) = InByte
DataIn(0) = DataInCount
End If
'Znak
if inbyte >=65 and inbyte <=90 then
znakcount +=1
znakin(znakcount) =inbyte
znakin(0)=znakcount
end if
Loop
end

[Saša]

Oh one more thing, you mast set direction out from port that is dedicated to PWM.
If is hardware you mast declare it. Or else it will not work. For PIC16F887 HPWM port is PORTC.2 (CCP1 - HPWM), so you must set DIR PortC.2 OUT

Good luck!