[ECOS] Questions about the eCos high level serial device driver

Michael Checky Michael_Checky@Thermoking.com
Tue Mar 18 10:06:00 GMT 2003

I'm in the process of writing a low-level serial device driver for a custom
serial device, and I have some questions about the design of the eCos high
level serial device driver.

1.  Why was 'serial_set_config' designed to call the low level 'set config'
routine for unrecognized configuration keys, but not 'serial_get_config'?
The reason I ask is that our system has the ability to select different
serial line transceivers, (EIA-232, EIA-422, EIA-485, ...), so I would like
to allow the user application to select these by using a custom key to '
serial_set_config', but it appears that the user can't query the custom key
using 'serial_get_config'.  I suppose I could use another custom key to '
serial_set_config' to return the configuration, but that is just a kludge.
Any suggestions and/or fixes to 'serial_set_config' ?

2. The user level callback 'status_callback' in 'struct serial_channel'
isn't documented.  Any particular reason? The reason I ask is that our
system is designed for block I/O but it can track communication errors for
each byte received.  I don't have enought information as to how this
interface was designed to be used.  Would it be better to call
'serial_indicate_status' on every error received or just read the entire
data block, keeping track of errors, and call it at the end?

3. We need to run TCP/IP over PPP.  Has PPP been ported to eCos?  If not,
do you know if anybody is doing so?  If not, do you have a feel for which
TCP/IP stack to use, OpenBSD or FreeBSD?  I assume the Linux PPP driver
would be the place to start a PPP port to eCos.  Any thoughts on this?

Michael Checky

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