The hy_vfd docs say that the default comms type is 8N1, and suggests
setting the VFD register 165 to 3 (8N1 RTU)

The VFD setting advice seems correct, but hy_vfd actually seems to
default to 8E1:

halcmd: loadusr hy_vfd --debug
halcmd: hy_vfd: device='/dev/ttyS0', baud=19200, bits=8,
parity='even', stopbits=1, address=1, debug=1, PID=24472
Opening /dev/ttyS0 at 19200 bauds (even)

The Internet is of the opinion that the VFDs don't work with parity of
either type enabled. A test with P165 set to 4 (8E1) and the default
hy_vfd config, however, seems to indicate that this is not true,
though a number of comms timeout messages are seen (as they are, with
my setup, with 8N1 too).
I think that response lag is higher (and significant) with 8E1.

So, do we change the docs to suggest P165 = 4, or do we change hy_vfd
to match the docs?

Actually, step zero is probably to ensure that when --debug says
parity even that this is actually correct.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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