serial communication time

[Mugelpower]

Thanks for your Help so long Guys.

As you know I will do as You tell and try. So I bought everything I need to try parallel com between pics but at first I will give "Debug" a try because its so fast (I read about that)

Sending (with all the Defines at Baud rate 9600)

CNT Var Byte
....
....
Debug [cnt]


Recieving (same Definitions)

Debugin ; cnt

.....
LCDOUT $FE02 `something like that, worked before
LCDOUT $FE80 "CNT=" , CNT
...

I´m not absolute shure about the code BUT

The LCD Display recieves something but only one Element which changes when changing the Input frequency
It shows CNT=§ (its the german symbol for "Divide" I dont have it on my keyboard)
or CNT=A (but only half symbol height and square)

This shows the transmission works, its just like different languages.
When I use Serout/Serin everything works fine
then it shows "CNT=146" for example whith input freq 146Hz .

There must be more about Debug/Debugin
I tried changing the Var defines from byte to dec which changed the display from rubbish to rubbish .

I thought if i´m sending a Var frompic to pic then it doesn´t change. Obvious it does.
What I´mmissing?
I´m showing the precise program code today in the evenig when I´m back home.
I need just a simple example for sending a byte by debug from pic to pic.
Oh yes I dream of baud rate 120000 or something....

[Mugelpower]

This is for sending the variable "CNT"
' DEFINITIONS
Include "modedefs.bas"
CMCON=%00000111
DEFINE OSC 4
DEFINE DEBUG_REG PORTB
DEFINE DEBUG_BIT 2
DEFINE DEBUG_MODE 0 '1 = Inverted, 0 = true
DEFINE DEBUG_BAUD 9600

Cnt VAR Word ' Cnt is a word variable
CMCON = 7 ' RA0-RA3 are digital I/O
TRISA = 0 ' PORT A is output
TRISB = %01111111 ' RB7 is Input others output
cnt = 0
main:

COUNT PORTA.2,100,cnt ' Count for 1 second
DEBUG cnt

goto main


END ' End of program

And this is for recieving

'
' DEFINITIONS
Include "modedefs.bas"
CMCON=%00000111
DEFINE OSC 4
DEFINE DEBUGIN_REG PORTB
DEFINE DEBUGIN_BIT 1
DEFINE DEBUGIN_MODE 0 '1 = Inverted, 0 = true
DEFINE DEBUGIN_BAUD 9600

Cnt VAR Word ' Cnt is a word variable
CMCON = 7 ' RA0-RA3 are digital I/O
TRISA = 0 ' PORT A is output
TRISB = %11111101 ' RB1 is Input others output
cnt = 0

main:


debugin [cnt]


LCDOUT $FE,2
LCDOUT "cnt=", cnt
goto main



goto main


END ' End of program
and it shows just rubbish as told in the post above.
Any Hint?`

[skimask]

LCDOUT $FE , 2 , "cnt=" , DEC cnt

Just like the good book says...
That rubbish you say was the ASCII representation of the value in cnt.

[Mugelpower]

Hi Skimask,

I did as You told but now my LCD shows

cnt=252 or cnt=253

thats the only change

Any hint?

Greetings from a desperate mechanical engineer

[Mugelpower]

Hi Skimask,

I changed my program into this:

'
' DEFINITIONS
Include "modedefs.bas"
CMCON=%00000111
DEFINE OSC 4
DEFINE DEBUGIN_REG PORTB
DEFINE DEBUGIN_BIT 1
DEFINE DEBUGIN_MODE 0 '1 = Inverted, 0 = true
DEFINE DEBUGIN_BAUD 2400

Cnt VAR Word ' Cnt is a word variable
CMCON = 7 ' RA0-RA3 are digital I/O
TRISA = 0 ' PORT A is output
TRISB = %11111101 ' RB1 is Input others output
cnt = 0

main:


debugin [cnt]


LCDOUT $FE,2 ' Home cursor
LCDOUT "CNT=", DEC3 Cnt

goto main



goto main


END ' End of program

Now it works but only with this Baud rate of 2400.

BUT I WANT a Baud rate of ONE ZILLION or so.

seems I´m still at the beginning.

Or is it possible to run the data transfer in the background using some asm code ?

Greetings from Mugel

[skimask]

Now it works but only with this Baud rate of 2400.
BUT I WANT a Baud rate of ONE ZILLION or so.
seems I´m still at the beginning.
Or is it possible to run the data transfer in the background using some asm code ?
Greetings from Mugel

I guess I still don't get what you're trying to accomplish in the end.

It probably works at 2400 baud because there's enough time in between transmitted characters to send the data out to the LCD. At higher speed, when PBP returns from displaying to the LCD, the next transmission/reception is already halfway done and it gets missed. Either that or your oscillator is out of tolerance.

As far as using high baud rates, no you don't really need asm code...just a good understanding of the PIC, it's registers, the USART module, and some interrupts.

And it seems I'm right back to saying what I said back on 1Feb...

[Mugelpower]

Hello famous Skimask,

my LCD is only for controlling the principal of transmission.

I got 3 Pics together:

1. : getting Input, storing freq in VAR "CNT" and sending out with Debug
2. : taking the VAR "CNT" with Debugin, calculating a Delay and sending out a 1ms Pulse
after RB0 gets High + Delay time.
3. : taking the VAR "CNT" and showing on LCD just for control purposes

Showing my extremes:

a)cranking a 4-cyl. engine makes about 180/min. with a fixed 50° before OT input signal we need a delay of 37 ms until Ignition which makes 10° before OT which is great for starting an engine.

b) 4cyl 8000/min: we need only 0.2ms Delay after fixed 50° Input signal to get 40° before OT Ignition which may be great for a racing engine.

The delay has to include the PICs intern calculation delay.
The calculation could be done in the first PIC which measures only 10 times a second
BUT the "Execution PIC" has only about 1.5 ms for receiving the Var and being ready for the next action.
And an 8cyl at 6000/min leaves only 0.8 ms.
thats why I need transmission speed