Wait for a string on a serial port

[richard]

MAIN:
SERIN2 DataIn,BdRate,[WAIT("Identifier"),Switch]
IF Switch = $31 THEN TX_ON = 1
IF Switch = $30 THEN TX_ON = 0
GOTO MAIN
END

or

in serialtool send

Identifier#1

[sayzer]

You have DEFINCE OSC 8 in your code with HS option in fuse.

OSCCON.0  = 0  ' Clock source defined by FOSC<2:0> of the Configuration Word register

This way, chip knows the clk source.

Default OSC value is for Internal 4Mhz clock.

Hope this will solve your issue.

[flotulopex]

Sayzer,

Sorry, i don't understand what I have done wrong with the OSC settings. I'm using an external 8MHz crystal; maybe I should have mentioned it.

I'll give Richard's suggestion (post #10) a try in a little moment and see what it does

[HenrikOlsson]

Richard is on it (as usual). Remember that when you're using the serial terminal you're sending ASCII characters. In your original code you're checking if the variable contains the value 1 while you should check if it contains the ASCII character "1".

IF SWITCH = 1
IF SWITCH = "1"
IF SWITCH = $31
IF SWITCH = 49

Do you see (and understand) the difference between the four lines above?

/Henrik.

[sayzer]

Sayzer,

Sorry, i don't understand what I have done wrong with the OSC settings. I'm using an external 8MHz crystal; maybe I should have mentioned it.

I'll give Richard's suggestion (post #10) a try in a little moment and see what it does

Hi Roger,


I know you are using external 8Mhz crystal, that is why you need to tell the chip about it.
In your code, there is no OSC setting. You have it in fuse.
Default OSC setting is internal 4Mhz.

You need to manually choose the OSC value for external source by OSCCON.0 = 0
Otherwise, chip will not know you have selected external HS.

To make sure you are running on the correct speed, have a flip flop on a pin for say 5000ms.

FlipFlop:

TX_ON = TX_ON ^ 1
PAUSE 5000

Goto FlipFLop

Then, you can see the speed.

[AvionicsMaster1]

Henrik, for my edification is this the correct answer? Please don't roll your eyes too far if this is too much of a NOOB question.

IF SWITCH = 1
IF SWITCH = "1"
IF SWITCH = $31
IF SWITCH = 49

IF SWITCH = 1 checks to see if SWITCH is set to ON
IF SWITCH = "1" checks to see if SWITCH is equal to an string value of 1
IF SWITCH = $31 checks to see if SWITCH is an ASCII 1
IF SWITCH = 49 checks to see if SWITCH is an ASCII 1

For the life of me I cannot discern the difference between the last two. $31 = 49 on the ASCII table. How are they different?

Thanks for your patience.

[flotulopex]

Default OSC value is for Internal 4Mhz clock.

Right, thanks for pointing this to me

[HenrikOlsson]

Henrik, for my edification is this the correct answer? Please don't roll your eyes too far if this is too much of a NOOB question.

Don't worry about any eyes rolling, this type of thing comes up quite often and hopefully we all learn from it.

All four lines obviously compares the value stored in the variable SWITCH with whatever value is on the right side of the equal sign. But out of the four lines, only the first one would make any difference compared to other ones when put into a program. The other Three would execute exactly the same because they all compare SWTICH to the a value of 49 (while the first line compares SWITCH to a value of 1).

1 is simply the value of 1
"1" however is the ASCII character 1 (which happens to correspond to the value 49 expressed in decimal notation).
49 is the ASCII code, expressed in decimal notation, for ASCII character "1"
$30 is the hexadecimal representation of the decimal value 30 which is the ASCII code for character we know as "1"
%00110001 is the binary representation of the decimal value 30 which is the ASCII code for the character we know as "1"

If, instead of camparing SWITCH to something you'd assign values to it:

SWITCH = 1
SWITCH = "1"
SWITCH = 49
SWITCH = $30
SWITCH = %00110001

Only the first line is different, the other four lines all does exactly the same thing - it's just different ways of expressing, or interpreting, the same thing.

/Henrik.

[flotulopex]

MAIN:
SERIN2 DataIn,BdRate,[WAIT("Identifier"),Switch]
IF Switch = $31 THEN TX_ON = 1
IF Switch = $30 THEN TX_ON = 0
GOTO MAIN
END

...or in serialtool send Identifier#1...

Thanks Richard, it works well expecting HEX values ($30 and $31) but it will not work with Identifier#1.

[richard]

Thanks Richard, it works well expecting HEX values ($30 and $31) but it will not work with Identifier#1.

command parsing needs to be enabled in your transmit window

[right click in tx window] to see menu

[flotulopex]

Thanks Richard. I should have tried this...