On 06/08/2017 06:59 AM, Beagle Boner wrote:
Hi,
i´m using the latest Debian Image an I´m trying to set an external RTC
as a hardwareclock for my BBB. I have a different RTC module (PCF8563)
but basicly I stick to the following manual:
https://learn.adafruit.com/adding-a-real-time-clock-to-beaglebone-black/set-rtc-time
What I dont understand here is the following:
The author sets the ds1307 as a new i2c device with the command:
echo ds1307 0x68>/sys/class/i2c-adapter/i2c-1/new_device
In the next step he can already access the new rtc1 device.
hwclock -r -f /dev/rtc1
Why is that? How does the system know that the new i2c device
connected is a RTC and how to access it. Is there a preinstalled
driver for DS1307?
The first command instructs the I2C adapter that there is a device at
address 0x68 and to match it with an I2C driver "ds1307". When the
driver loads, it creates a new /dev/rtcX device (and also a new
/sys/class/rtc/rtcX device).
According to the manual I did the following:
echo pcf8563 0x51 > /sys/class/i2c-adapter/i2c-2/new_device
My PCF8563 is getting recognized as rtc1 (not sure why - I havent
installed any drivers?)
The beaglebone kernel includes the driver for this device.
When I try to access
hwclock -r -f /dev/rtc1
I just get
hwclock: ioctl(RTC_RD_TIME) to /dev/rtc1 to read the time failed:
Invalid argument
Does anyone have some hints on that?
Which pins are you using? Have you set the pin mux for I2C? Can you read
any of the files at /sys/class/rtc/rtc1/* ?
Cheers.
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google
Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to beagleboard+unsubscr...@googlegroups.com
<mailto:beagleboard+unsubscr...@googlegroups.com>.
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/9645489d-9a24-4888-b124-e3eeac3f0811%40googlegroups.com
<https://groups.google.com/d/msgid/beagleboard/9645489d-9a24-4888-b124-e3eeac3f0811%40googlegroups.com?utm_medium=email&utm_source=footer>.
For more options, visit https://groups.google.com/d/optout.
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/beagleboard/11616938-31d2-b8de-9db7-8dd2b23ec862%40lechnology.com.
For more options, visit https://groups.google.com/d/optout.
