Text buffer

[nuclear__]

Hi. I'm experimenting on how to use a text buffer in the correct way.
For example i want to write text and variables for debug purposes in a large buffer and then call a routine every second that will print the buffer to lcd and or to usb (could be uart too).
I have nothing to show up. I achieve that in some ways but i don't make use of functions like rcv_buffer_bytes, or others that i don't know exactly how they work.
Can someone give me a versatile example on the optimum way to send text in a buffer within the code ?
I have made a board with 18f45j right now and play with that. I have working usb and lcd.

[temtronic]

There is no 'correct' way. How you display the data really is up to you.
You say 'large' buffer but LCD modules tend to be 16x2 or 20x4 in size, not really 'large' so typically maybe 5-8 variables get displayed on a fixed format screen.
If sending data to a PC you could see more data on the PC screen, say 1000 characters, however that is a LOT of data to look at especially if updated every second.
For large data transfers a transmit ISR would be the best method, CCS has supplied a working example of this in the 'examples' folder.

However you mention 'rcv_buffer_bytes' which implies the PIC getting data NOT sending it so we need more information of what you really want to do.

Jay

[nuclear__]

Ok, lets forget rcv_buffer.
I'm using lcd flex driver, so i use this command to print:

[Ttelmah]

If you look in the compiler examples, at ex_sisr.c, this is a serial receive buffer (now I know you want to transmit...). However the basic principles of a 'circular buffer' can be used for anything....
What you have is two 'counters', that chase each other round a 'ring' of storage locations. Now the actual ring is physically linear in memory, but each buffer 'wraps' when it gets to the end of the buffer, so it behaves as if it is a ring.

To add a character, you just write it to the 'next_in' location, and increment this counter (with wrap if necessary). If it has 'caught up' with the 'out' counter, than you have a potential 'overflow', and have to decide what to do (wait, throw something away etc..).
You can at any time tell if something is in the buffer by just testing if next_in==next_out. If so, then the buffer is empty. You never have to actually 'clear' anything, just set next_in to equal next_out, and the buffer will be 'empty'.
To read, you just test if there is a character (next_in!=next_out), and if there is read the character from 'next_in', and then increment this (with wrap).

It's a very good way of handling lots of I/O tasks on any processor.

Now as posted, there is a problem with the way it wraps the buffer unless you use 'binary' buffer sizes (2,4,8,16 etc.), but how to fix this has been posted here many times. The nice thing is you can just call your buffer write something like 'bputc, and then use:

[nuclear__]

Very nice! I will approach your solution. A lot of homework.
Thanks