Re: 1-wire behaviour on Bookworm

On 22/09/2024 at 11:53, John Aldridge wrote:

In article <vckmfh$17vkc$2@dont-email.me>, news@druck.org.uk says...

>
On 20/09/2024 11:17, John Aldridge wrote:
[Reading ds18b20 sensors in parallel]

No, but AIUI the "right" way to do this is to send the text "trigger" to
/sys/bus/w1/devices/w1_bus_master1/therm_bulk_read before reading the
values as normal. The trigger causes them all to start a conversion at
once, following which the reads all complete immediately once a single
conversion time has elapsed.
>
As a quick hack, try executing the following before reading your
sensors...
>
sudo su <<EOF
echo trigger > /sys/bus/w1/devices/w1_bus_master1/therm_bulk_read
EOF

>
Thanks, that seems to works for the first bus, but I get a permission
denied when using w1_bus_master2.

 Sorry, I've no idea why that might be :(
 Though I do recall the permission checking being a bit odd -- hence the
"sudo su" rather than a plain "sudo".
 

Have you tried
'echo trigger | sudo tee /sys/bus/w1/devices/w1_bus_master1/therm_bulk_read'
--
Chris Elvidge, England
HIGH EXPLOSIVES AND SCHOOL DON'T MIX