[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [gpsd-dev] PPS over USB

From: Ed W
Subject: Re: [gpsd-dev] PPS over USB
Date: Mon, 07 May 2012 13:41:33 +0100
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:12.0) Gecko/20120428 Thunderbird/12.0.1

On 07/05/2012 04:20, Eric S. Raymond wrote:
Hal Murray<address@hidden>:
Is there a list of serial-USB chips that are known to work and/or not work?
You can generate one by grepping for TIOCMIWAIT in the driver tree.  Gary
did this as one point.  The PL2303 is defintely good, the CP210x bad.

Apart from PPS signals, does TIOCMIWAIT improve gpsd accuracy in any other way? Phrased another way are CP210x any worse than a generic PL2303 device?

I couldn't get a definite opinion, but CP210x devices appear to be USB2? I currently see around 1ms jitter on my device using just the NMEA clock - perhaps I ought to be expecting lower than this?

I think TIOCMIWAIT could be added to the driver. However, does this buy me anything on generic non PPS devices? Any other changes which would improve precision of the NMEA date?

Big picture question - Am I going to get better accuracy using your new device than I am from these CP210x Venux6 devices?


Ed W

reply via email to

[Prev in Thread] Current Thread [Next in Thread]