Re: [ECOS] Problem with getchar / gets / fgets

[Peter Graf <p dot graf at itknet dot de>]

Nicolas Brouard wrote:

> Hi,
> Does somebody have a council to solve my problem?
> I have a Shell application and input lost a lot of characters. On my PowerPc
> MPC860 target, I have to hit each character several times to display it on
> minicom.
>  
IIRC you reported that Redboot worked fine, so it reminded me of having 
a similar problem. I can only refer to eCos 2.0, but I guess this has 
not changed. In io/serial...serial.c, serial_read() attempts to fill a 
buffer of more than one character, even if the upper layer has requested 
only one, e.g. when the caller was getchar(). Now when your lowlevel 
driver supports no interrupt driven buffer fill operation (reflected 
here by cbuf->len==0), this will be done by calling several blocking 
(funs->getc)(chan), i.e. you must send several characters until the 
buffer is filled and serial_read() decides to return to its caller. 
Check if the characters properly arrive in your lowlevel driver first. 
If they do, it might be related to this. I resolved it by a quick hack 
in serial.c, never blocking for more than one character, but the proper 
way is an interrupt driven lowlevel driver.

Peter


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