Serial from PC into an Array

[andyf]

I have managed to make a really cool design that is perfect for testing the PIC16F877-20/P is getting what I send it. it simply echo's back to the PC what Is recieved at 19,200 on a 20MHZ clock.

ok, so this is great and runs sweat, even have several subroutines to act upon the data/codes I send the PIC.

Now I have a short and simple problem and am sure the answer will be very obvious so here goes.

HSERIN [WAIT("*TEST"),STR in_ctl\11\"*"]

in-ctl is an array that can contain upto 24 characters, the question is how can I know if it only has 6, 7 10 20 etc...

input string examples:
TESTABCDEF! in-ctl contains 7 characters
TESTABCDEFGHI! in-ctl contains 10 characters
TESTABC! in-ctl contains 3 characters

I want to do this so I can have a loop similar in practice to this syntax:

AR = arreycount(in-ctl)
do
.
. some code
.
X=X+1
loop until X = AR


Andy

[Dave]

andyf, What I used to do is make sure the receiving array is all null by clearing it in a sort of loop. Then using the HSERIN options of "STR arrayname/maxumum characters/13" will load the array with no more than the maximum characters and terminate the input or, any number of characters until a carriage return is encountered. Then within some sort of loop look for the last character to be null and that is the last received character. Something simillar to this code:
Counter = 0
While counter <= maxcharacters
in_ctl(counter) = 0
Counter = Counter + 1
wend
HSERIN [WAIT("*TEST"),STR in_ctl\Maxcharacters\13]
Counter = 0
While (in_ctl(Counter) <> 0) and (Counter < Maxcharacters)
Counter = Counter + 1
wend
'At this point Counter has the number of characters in the received array -1

Dave Purola,
N8NTA

[mister_e]

Good idea Dave.

If you want to have another way,
Here's is another way

[NavMicroSystems]

You could send a single byte containing the length of the string.
Send this byte right after the "SYNC" string (*TEST)

STR in_ctl[0] would then tell you how many valid chars are in this array.

[Dave]

Mister-e, That is an OK way to do it at a slower baud rate but at 9600+ baud I would be concerned with loosing characters especially at lower osc frequency's.

Dave Purola,
N8NTA

[mister_e]

Dave,

you're 100% right on that, was just an example snip. For faster Baudrate I'll for sure prefer using an other way like yours or Ralph's suggestion. Well, serial communication handling is an endless story and depend of too much thing to have an single solution