Hserout/Hserin via bluetooth

Hello boys,

I need a little alignment about serial communication via HC-5 bluetooth modules. I try to send via bluetooth 8bit ADC value from one MCU to another MCU and this value feed to MCP41010 digital pot.
I succesfully setuped and paired the bluetooth modules but I have trouble with receiving data. If I feed the data on receiver side to serial monitor on PC I saw changing correct values from 0 to 255 as I changing the pot value on transmitter side.
But in "datain" variable (on LCD) I dont have a correct value like 0 to 255. Value from 0 to 9 is correct but next is "random" numbers.
What is the right way to receive these value to datain variable?

Thanks.

The codes for
receiver:

Code:

---

; device PIC 16F688
#CONFIG
cfg = _INTRC_OSC_NOCLKOUT
cfg&= _WDT_ON
cfg&= _PWRTE_OFF
cfg&= _MCLRE_OFF
cfg&= _CP_OFF
cfg&= _CPD_OFF
cfg&= _BOD_ON
cfg&= _IESO_ON
cfg&= _FCMEN_ON
 __CONFIG cfg
#ENDCONFIG
 
DEFINE OSC 8      ; Use a 8 MHZ internal clock
OSCCON = %01110000

DEFINE HSER_RCSTA 90h ; Enable serial port & continuous receive
DEFINE HSER_TXSTA 24h ; Enable transmit, BRGH = 1
DEFINE HSER_BAUD 9600 ; 9600 Baud
DEFINE HSER_CLROERR 1 ; Clear overflow automatically

Define LCD_DREG PORTC
Define LCD_DBIT 0
Define LCD_RSREG PORTA
define LCD_RSBIT 4
define LCD_EREG PORTA
define LCD_EBIT 5
define LCD_BITS 4
define LCD_LINES 2
define LCD_COMMANDUS 2000
define LCD_DATAUS 50

ANSEL = 0          ; Set all digital
CMCON0 = 7
TRISA = %000000    ; Set all output
TRISC = %000001    ; Set RC.5 input

SCK    var    PORTA.0    ; Alias PORTA.0 to SCK (serial data clock)
SDO    var    PORTA.1    ; Alias PORTA.1to SDO (serial data out)
CS      var    PORTA.2    ; Alias PORTA.2 to C_EN (chip enable)

datain var byte

PAUSE 500 : LCDOUT $FE,1 : PAUSE 250 ; Initialize LCD 
HIGH    CS                          ;Chip enable high to start MCP41010 digital pot
high    sck                          ; Mode 1,1 SCK idles high
pause 10
 
Pot0 con %00010001                  ; digital pot command setting

Main:
LCDOUT $FE,1
HSerin 500,main,[dec datain]        ; read from bluetooth. Value between 0 - 255
pause 30
lcdout $FE,$80,dec datain            ; lcd out only for information
pause 30

low CS                                ; Make digital pot chip active
pause 1                             
shiftout  sdo,sck,5,[pot0,datain]    ; Mode 1,1 / Mode 5 - clock idles high, datain value shift out
high CS
pause 1

goto main

---

transmitter:

Code:

---

; device PIC 16F688
#CONFIG
cfg = _INTRC_OSC_NOCLKOUT
cfg&= _WDT_ON
cfg&= _PWRTE_OFF
cfg&= _MCLRE_OFF
cfg&= _CP_OFF
cfg&= _CPD_OFF
cfg&= _BOD_ON
cfg&= _IESO_ON
cfg&= _FCMEN_ON
 __CONFIG cfg
#ENDCONFIG
                         
DEFINE OSC 8            ; Use a 8 MHZ internal clock
OSCCON = %01110000

Define ADC_BITS    8  ; Set number of bits in result
Define ADC_CLOCK    3  ; Set clock source (3=rc)
Define ADC_SAMPLEUS 50  ; Set sampling time in uS

DEFINE HSER_RCSTA 90h ; Enable serial port & continuous receive
DEFINE HSER_TXSTA 24h ; Enable transmit, BRGH = 1
DEFINE HSER_BAUD 9600 ; 9600 Baud
DEFINE HSER_CLROERR 1 ; Clear overflow automatically

adval var byte

ANSEL = %10000000  ; Set AN7 analog input, rest digital
CMCON0 = 7
TRISA = %000000    ; Set all output
TRISC = %001000    ; Set RC4 output TX pin

let adval = 0

main:
ADCIN 7, adval
pause 20
hserout [dec adval,10]  ; hserout adval to bluetooth HC-05
pause 20
GOTO Main

---

In your receiver code, how are you determining the entire data string has been sent?

That's what I don't know.

If I try this on transmitter side:

Code:

---

main:
adcin 7, adval
pause 20
hserout [hex adval,13,10]
pause 20
goto main

---

and on receiver side:

Code:

---

main:
lcdout $fe,1
hserin 500, main, [hex datain]
pause 20
lcdout $fe,$80, dec datain
pause 20
goto main

---

It works, but the result on LCD is unstable, the value sometimes jumping between 0 -255 randomly.
I think this is not the right way how to send and receive serial data via BT .

Can I use hserout [dec adval,13,10] on transmitter side?

What about on receiver side hserin 500, main, [hex datain] not work,
maybe hserin 500, main, [str datain\3] ?

I don't know how to read the sended decimal value in to the datain variable. On receiver side right on output from HC-05 I have correct serial decimal value 0 - 255, verified by serial monitor on PC.

Sending data via an HC bluetooth module is no different to sending it via normal serial, just that there is no physical cable between the two devices (such as a PC and the PIC).

You could try using an FTDI usb to serial module and get the code working via hardwired setup and then use the HC module which should function exactly the same, if it doesn't then this would suggest that there may be a fault with the hardware.

I use these in a couple of my projects to send decimal values from word variables to an application running on a PC

Code:

---

HSEROUT [dec4 CH1_MAX]
HSEROUT [dec4 CH2_MAX]

etc

then
HSERIN 1000, RX_Bombed, [dec4 CH1_MAX]
to read it back

---

The RX Bombed is a time out

Code:

---

RX_Bombed:
    TimeoutCount = TimeOutCount + 1
    end select
Goto main

---

I then have this bit of code at the start of my comms subroutines

Code:

---

coms:

HSERIN [nTest]
    SELECT CASE nTest
    CASE "Q"                    ; if Q then send data to PC
    Goto Term_TX
    CASE "S"                    ; if S then receive data from PC
    goto Term_RX
return

---

In the main program loop I have this to check the buffer and jump to the comms subroutine

Code:

---

FOR TempWD = 0 TO 500
    IF RCIF=1 THEN GOSUB coms                  ; Check to see if PC application connected
    PAUSE 1
next TempWD

---

Hope this helps

Sorry for got to add

Code:

---

RCIF                VAR PIR1.5                    ' USART receive flag

---

Thank You for answer, maybe I found the problem. If I comment the "lcdout $fe,$80, dec datain" and "lcdout $fe,1" lines in my code the value in datain var come correct an stable.
Then I put the datain value to other variable like:

Code:

---

main:
hserin 500, main, [dec3 datain]
pause 10
let lcd_out = datain
lcdout $fe,$80, dec3 lcd_out
pause 20
goto main

---

And it works how I wish, luckily :-)