Pyserial not getting response every time, input/output errors
grante at visi.com
Tue Aug 12 22:33:52 CEST 2008
On 2008-08-12, Carsten Haese <carsten.haese at gmail.com> wrote:
> Rainy wrote:
>> I'm having some trouble with pyserial package, I'm sending commands
>> and reading responses from a custom pcb, and sometimes I get a proper
>> response, at other times I get nothing, and sometimes I get about half
>> of the response string with beginning cut off. About half the time an
>> empty string is returned, the other ~half time good response, and more
>> rarely I get partial response.
>> When I try to use the same Serial instance to send/receive a few
>> times, I end up getting an input/output error.
>> Here are some examples:
>>>>> ser = serial.Serial('/dev/ttyAM1', 115200, timeout=0.1)
> One possible point of failure is that you're not supplying any
> parameters for the data format (byte size, parity, stop bits) and flow
> control. The Serial object will assume defaults, and those defaults may
> or may not be correct.
None of those things are capable of creating an input/output
error -- you'll just get goofy data values (or no answer from
the device at the other end of cable). An input/output error
usually means that there are issues with the underlying bus or
there are hardware failures.
> Try to find out what data format and flow control you should
> be using and set explicit Serial parameters accordingly.
Grant Edwards grante Yow! ... If I had heart
at failure right now,
visi.com I couldn't be a more
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