HSerSend interruption

[JANIS]

Hello!
To understand the problem, I will tell you about my project. There are two devices - one device has a 3x7 segment display that indicates the temperature of the DS18B20 or running messages. The display mode depends on the temp value of the Hserreceive from the other device. The other device will consist of a fan control with HPWM, a photo sensor of the analog input, a timer, led by HPWM ... depending on the mode of operation, the second device sends a display byte through Hsersend, which will set the display mode. I created a test code for both devices. The main problem is that the byte tempvalue that is sent from the second device to the display through the serial port is unstable. The test code is intended to test how HserSend works. The test sends 3 values ​​(0, 1, 2) each at a time. Everything works at least normal, unless the program code contains the HPWM instruction ... Inserting the program code into HPWM, Hsersend begins to byte broadcast intermittently. Due to this, the display starts to distort the running message. I have no communication experience. I can not continue to build the program code :( Help ludz. I hope you understand my story.
I add both program codes.

second device program code (tx)

 #chip 16F886, 4
#config osc=int

 ;Setup LCD Parameters
  #define LCD_IO 4
  #define LCD_NO_RW
 '' #define LCD_Speed fast
; ----- Define Hardware settings
  #define LCD_RS PORTc.4
  #define LCD_Enable PORTc.5
  #define LCD_DB4 PORTb.3
  #define LCD_DB5 PORTb.2
  #define LCD_DB6 PORTb.1
  #define LCD_DB7 PORTb.0

dir portc.2 out
tempvalue=0

#define USART_BAUD_RATE 9600
Dir PORTc.6 out  ' Tx 'Set USART transmit pin to output
dim aa as word
cycle:

''  test programmm
aa++

if aa=>4000 then aa=0
if aa<1000 then tempvalue=1
if aa>1000 & aa<2000then tempvalue=0
if aa>2000 then tempvalue=2

   HSerSend tempvalue

locate 0, 0

Print "Hello World."

HPWM 1, 40, 26

wait 10 ms
goto cycle

Display DEVICE CODE (Rx)

  #chip 16F886, 4

  #config osc = int
    #define 7Seg_Commonanode
    'support for pfet or pnp high side drivers - speciali prieks draiveriem!
  ''#define 7Seg_HighSide
    #define DISP_SEG_A PORTB.0
    #define DISP_SEG_B PORTB.1
    #define DISP_SEG_C PORTB.2
    #define DISP_SEG_D PORTB.3
    #define DISP_SEG_E PORTB.4
    #define DISP_SEG_F PORTB.5
    #define DISP_SEG_G PORTB.6
    #define DISP_SEG_DOT PORTC.1

    #define Disp_Sel_1 PortA.1
    #define Disp_Sel_2 PortA.2
    #define Disp_Sel_3 PortA.3
dir portb out
    dir porta.1 out
    dir porta.2 out
    dir porta.3 out
    dir portc.1 out
    ''------------
    ''  temp sensor settings
#include <DS18B20.h>
' DS18B20 port settings
#define DQ PortC.4
''  display settings
InitTimer0 Osc, PS0_16''  0_16 pie 4mhz
On Interrupt Timer0Overflow Call showdigit

dig =1

 ''======================
   'USART settings
  #define USART_BAUD_RATE 9600  'sets up comport 1 for 9600 baud

'               'Set USART receive pin to input
 Dir PORTC.7 In
 ''============
  time=0
  time_1=0
char=0
dim message as string
   signneg=0
   signpos=0

  main:

  ''=================================
HSerReceive tempvalue
filt++
if filt=>50 Then
tempvalue1=tempvaluereceived
filt=0
end if

  ''====temperature reading
  if tempvalue=0 then

  time=0
  time_1=0

   ReadDigitalTemp

  If RxData.7 = 1 Then
  sign=1
      signneg++  ''  filter
    if signneg=>10 then
    signneg=10
    signpos=0
    end if
    DSint = 0 - DSint 
    ''Negative numbers 
    Else
       signpos++''  filter
    if signpos>10 then
    signpos=10
    signneg=0
    end if

    sign=0
    DSint =DSint
    end if

end if
Num3 = DSInt/10
Num2 = DSInt%10

      ''================================
if tempvalue=2 then
Message = "SECURITY "
char=9
speed=40
end if

if tempvalue=1 then
Message = "FAN ON "
char=7
speed=40
end if

if  tempvalue=255 then
Message = "CO FAULT "
char=9
speed=30
end if

''=================
if tempvalue>0 then
time++
     if time=>speed then
       time_1++
     if time_1=>char then time_1=0
      time=0
       end if
DisplayChar 1, Message(time_1), 1
Wait 3 ms
  DisplayChar 2, Message(time_1+1), 1
  Wait 3 ms
  DisplayChar 3, Message(time_1+2), 1
  Wait 4 ms
end if
   goto main
''==================================

sub  showdigit

if tempvalue = 0   then
    dig++
    If dig > 3 then dig =1

    Select Case dig
case 1
 If signneg=10 then  Displaychar 1, 45, 1 '' 45 - minus character ASCII
if signpos=10 then Displaychar 1, "C", 1
'display, character, normal dot 1=yes , invert dot 1=off)
 ''two undocumented ascii characters for the 7 segment display,
''space and minus (32 and 450). Otherwise the DisplayChar function must be a letter or number.
    Case 2
     if sign=1 then
    DisplayValue 2, Num3, 1                                              
    Else
     DisplayValue 2, Num3, 0
     end if
    Case 3
 DisplayValue 3, Num2, 1
    Case Else
        dig = 1
    End Select

  end if
end sub

[JANIS]

Also, the lcd display function interferes with serial port operation. for example cls and other lcd instructions. but my project will also have a display provided.

[mmotte]

JANIS,

You have chosen to experience one of the most popular problems. Communicating between two PICs.

use "Divide and Conquer" troubleshooting. You have a display on both ends of the comm line. use extra print/display statements on both PICs to see what is happening. Also slow things down( longer wait) so they become more apparent where the problem lies.

On the Tx Pic, i don't think the HPWM statement should interfere.
I would use your LCD to print both the "aa" value and the the "tempvalue" variables to the LCD.

On the Rx PIC i do see a conflict. When reading temperature you are using the 3x7seg display to display using the interrupt "showdigit" to jump between digits at intervals of timer0. For the messages you are not using the interrupt but driving them directly with DisplayChar which is overriding the other display. We need to make the "showdigit" into a "showchar" intterrupt sub so they are not in conflict.
OR shut the interrupt off when not using it. I like the first option of making it work with both char and numbers.

Another problem is "HSerReceive tempvalue". HSerReceive sends back a default value(255) if there is no data available. You need to check for new data if you want to receive only you data(0,1,2).

'If there is no new data, HSerReceive will return default value.
        comport = 1
        HSerReceive Rxvalue
        If Rxvalue <> 255    Then    ‘ don’t change your value if it is default
             tempvalue = Rxvalue
        End If

Even better way is:

If USARTHasData then
    HSerReceive tempvalue
    End If

I hope this helps. i will look at rewriting the "showdigit" intterrupt routine to do both as time allows.

GL
Mike

[Anobium]

Why not try I2C between the two? Works ok.

[JANIS]

Thanks, mmotte! I will try!

Anobium, as I said, I have no experience with communications. this is the first project. The devices will be connected by cable of approx. 1.5m ....

[JANIS]

I tried
If USARTHasData then HSerReceive tempvalue End if
Its work!

I2C is a short distance. How much is the maximum distance?
I have a question, where is the description in Help about the USARTHasData command?