Serial Communication

[Kaka]

Hi Guys,
I am new user of Great Cow. I am trying to communicate 2 MCUs. The process is first MCU will send data to second MCU; this will do some calculations on received data and send back to first MCU, it will verify this data. That’s it.
The problem is when first MCU receive calculated data from second MCU it’s not the data sent by second MCU. Please tell me what i am doing wrong.

First MCU Code

;Chip Settings
#chip 16F887,8

;Defines (Constants)
#define LCD_IO 4
#define LCD_RS PORTB.2
#define LCD_NO_RW 1
#define LCD_Enable PORTB.3
#define LCD_DB4 PORTB.4
#define LCD_DB5 PORTB.5
#define LCD_DB6 PORTB.6
#define LCD_DB7 PORTB.7

#define SerialOut       PORTC.6 'Pin 25
#define SerialIn        PORTC.7 'Pin 26

#define USART_BLOCKING
#define USART_BAUD_RATE 9600
#define USART_DELAY 1 ms

;Variables
Dim Temp As Byte
Dim cTemp1 As word
Dim cTemp2 As word
Dim String as word


cTemp1 = 45

Cls
Print "Sending:"
Print cTemp1
Print " "
cTemp2 = cTemp1 + 5
cTemp2 = cTemp2 / 2
cTemp2 = cTemp2 + 2

HSerPrint Chr(cTemp1)
Wait Until USARTHasData
Temp = HSerReceive
Locate 1,0
Print "Reciving:"
Print Temp

Second MCU Code

;Chip Settings
#chip 16F887,8

;Defines (Constants)
#define LCD_IO 4
#define LCD_RS PORTB.2
#define LCD_NO_RW 1
#define LCD_Enable PORTB.3
#define LCD_DB4 PORTB.4
#define LCD_DB5 PORTB.5
#define LCD_DB6 PORTB.6
#define LCD_DB7 PORTB.7

#define SerialOut       PORTC.6 'Pin 25
#define SerialIn        PORTC.7 'Pin 26

#define USART_BLOCKING
#define USART_BAUD_RATE 9600
#define USART_DELAY 1 ms

;Variables
Dim Temp As Byte

Wait Until USARTHasData
  Temp = HSerReceive

  Print "Reciving:"
  Print Temp
  HSerPrint Temp

  Temp = Temp + 5
  Temp = Temp / 2
  Temp = Temp + 2

  HSerPrint Chr(Temp)
  Locate 1,0
  Print "Sending:"
  Print Temp

[mmotte]

I tried your "calculator" chip program and had trouble with the CHR().in your line"HSerPrint Chr(Temp)". Just use" HSerPrint Temp" because you don't need to convert to ascii.using the chr command.

Also "Wait Until USARTHasData" is redundant because you have defined "#define USART_BLOCKING" above and that takes care of waiting for the next received byte.You don't need the wait statement.

GL
Mike

[Kaka]

Thanks for reply mmotte, as you said i tried the following code. but no success. after removing chr command second MCU is getting 52 instead of 45.

MCU1

;Chip Settings
#chip 16F887,8

;Defines (Constants)
#define LCD_IO 4
#define LCD_RS PORTB.2
#define LCD_NO_RW 1
#define LCD_Enable PORTB.3
#define LCD_DB4 PORTB.4
#define LCD_DB5 PORTB.5
#define LCD_DB6 PORTB.6
#define LCD_DB7 PORTB.7

#define SerialOut       PORTC.6 'Pin 25
#define SerialIn        PORTC.7 'Pin 26

#define USART_BLOCKING
#define USART_BAUD_RATE 9600
#define USART_DELAY 1 ms

;Variables
Dim Temp As Byte
Dim cTemp1 As word
Dim cTemp2 As word
Dim String as word

cTemp1 = 45

Cls
Print "Sending:"
Print cTemp1
Print " "
cTemp2 = cTemp1 + 5
cTemp2 = cTemp2 / 2
cTemp2 = cTemp2 + 2

HSerPrint cTemp1
Temp = HSerGetString
Locate 1,0
Print "Reciving:"
Print Temp

If cTemp1 = cTemp2 Then
        Print "OK"
Else
        Print "NOT OK"
End If

MCU2

;Chip Settings
#chip 16F887,8

;Defines (Constants)
#define LCD_IO 4
#define LCD_RS PORTB.2
#define LCD_NO_RW 1
#define LCD_Enable PORTB.3
#define LCD_DB4 PORTB.4
#define LCD_DB5 PORTB.5
#define LCD_DB6 PORTB.6
#define LCD_DB7 PORTB.7

#define SerialOut       PORTC.6 'Pin 25
#define SerialIn        PORTC.7 'Pin 26

#define USART_BLOCKING
#define USART_BAUD_RATE 9600
#define USART_DELAY 1 ms

;Variables
Dim Temp As Byte

Temp = HSerReceive

Print "Reciving:"
Print Temp
;HSerPrint Temp

Temp = Temp + 5
Temp = Temp / 2
Temp = Temp + 2

HSerPrint Temp
Locate 1,0
Print "Sending:"
Print Temp

i am attaching Proteus file so you can test it your self. Thank you so much.

[William Roth]

Hi,

When sending serial data between MCU's it is probably a good idea to send/receive the data in its raw format. What I mean is NOT in Ascii format. This means using Hserout and HserReceive rather than Hserprint, Hsergetstring, etal

When troubleshooting code, I generally reduce the code to its most simple terms as a starting point.

In testing, I had trouble using the sub < HserReceive1 data > This did not return a correct value. However the function < data = HserReceive1 > Works OK. We need to look into why the sub does not work correctly.

Here is code that tested to work well. You will need to change Pins, etc as required by your chips

Sending Code:

#chip 18F25K22, 16
#config OSC = INTIO67

   'Using SWI2C for Display
#define I2C_MODE Master
#define I2C_DATA PORTB.4
#define I2C_CLOCK PORTB.5
#define I2C_DISABLE_INTERRUPTS ON
#define LCD_IO 10
#define LCD_I2C_Address_1 0x4E

'-----------------------------
#define USART_BAUD_RATE 9600
#define USART_BlOCKING
DIR PortC.6 out    '// TX1 Pin 17
DIR PORTC.7 IN     '// PIN 18
'-----------------------------

CLS
Wait 1 s
Locate 0,0
Print "Hardware Serial Test"
Wait 1 s : Cls
main:

Do
  For send_data = 0 to 255
    Locate 0,0: Print "Sent: "
    Locate 0,6: Print "   "
    Locate 0,6: Print Send_data

    Hsersend Send_data, 1  '//send data from USART1

   'Hserreceive1 Rec_data    '// ** Does not work ! **
    Rec_data = HserReceive1  '//wait for return byte

    Locate 2,0: Print "Received: "
    Locate 2,10: Print "   "
    Locate 2,10:  Print Rec_data
    wait  1 s   '//time to see data
  next
loop

---

Receiver Code

#chip 16F1829, 16

#define USART_BAUD_RATE 9600
#Define USART_BLOCKING

DIR PORTB.7  OUT  '// Tx Pin 10
DIR PORTB.5  IN   '// Rx Pin 12

Do
   'Hserreceive1 Rec_byte   '// THIS DOES NOT WORK !

   Rec_byte = hserreceive1   '// Use function !
   Wait 5 ms
   HserSend Rec_byte, 1
Loop