Re: [ECOS] Interrupts and Serial Ports

[Giridhara R P <rpgiri at cdotb dot ernet dot in>]

hi,
	In cyg_io_read, make sure that length should not be zero
(len!=0).
len = sizeof(buf).
cyg_io_read(handle, buf, len)
try this in blocking mode.
 


On Mon, 8 Nov 2004, Steve Knowlton wrote:

> Andrew,
> 
> Thanks for the response. I'm pretty sure I am using the full driver and 
> not the one for diagnostic output. I have the ports set up as /dev/ser0 
> and /dev/ser1 in the config
> tool. I just need to know the correct way to read data from the port.
> 
> I have set up a handle to the port using the cyg_io_lookup function and 
> configuring
> it to 9600 baud ( plus the other parameters such as stop bits etc ) and 
> set up
> for non blocking reads. I am looping through the cyg_io_read function at 
> a rapid
> rate but am still not reading anything. I know that polling is not the 
> best way to do
> this but I don't know how to set up an interrupt driven scheme since the 
> driver is
> already using the interrupt vector. Is there a way to hook onto this 
> interrupt vector
> so that I can use this interrupt to signal the arrival of data at the port?
> 
> Thanks
> 
> Steve
> 
> Andrew Lunn wrote:
> 
> >On Fri, Nov 05, 2004 at 08:33:07AM -0500, Steve Knowlton wrote:
> >  
> >
> >>I have an EB40A board. I am trying to read an incoming data stream on 
> >>Serial Port 1
> >>that arrives about every 15 sec. I can see the Rx LED on the port 
> >>flashing every time
> >>a packet arrives.
> >>
> >>I am trying to read data coming into the port using cyg_io_read using a 
> >>polling method.
> >>
> >>I was reading the documentation on the ecos serial driver and it claims 
> >>that the
> >>incoming data is buffered until it is read. Is this true because it 
> >>doesn't seem to work
> >>that way. I never seem to read anything from the port. I have tried both 
> >>blocking
> >>and non blocking reads. Occassionally I get a -11 error which means that 
> >>the data is
> >>not available and that the user should try again later. The returned 
> >>length is always 0 so
> >>that seems to prove that I am not reading anything.
> >>
> >>This does not seem to be a very good method and I was wondering if there 
> >>is an ecos interrrupt routine I can use that would execute whenever data 
> >>arrives at the port.
> >>Presumably ecos assigns an interrupt vector for the port. If so, how can 
> >>I use this?
> >>    
> >>
> >
> >eCos comes with two serial drivers. There is a very basic one as part
> >of the HAL. This is designed for diagnostic output and is
> >polled. There is also a full serial driver which is interrupt
> >driver. You should make use of this full serial driver and you should
> >then get better results.
> >
> >        Andrew
> >
> >
> >  
> >
> 
> 


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