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

[Jonathan Larmour <jifl at eCosCentric dot com>]

Michael Checky wrote:
> 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' ?

Unfortunately it's pretty set in stone now, so we'll just have to deal 
with it and use set_config underneath for everything.

> 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?

I don't think block devices were really considered in the design. Do 
whatever your application needs :-). Although if I had a preference or you 
were going to contribute this driver back, I'd indicate it for each error 
- that's more analogous to the "true" serial case.

Jifl
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