2011-07-16 09:56:29 PTP on Blackfin Linux
Wojtek Skulski (UNITED STATES)
I am looking for info on running PTP on Blackfin Linux. I have read the wiki page docs.blackfin.uclinux.org/doku.php?id=uclinux-dist:ptp as well as the BF518 HRM chapter 23 on IEEE 1588 PTP ENGINE. My understanding is that ptpd will "automagically" adjust the hardware clocks between two BF518 boards, one being master and one being slave. The precision of this adjustment is 12.5 ns claimed in the BF518 Data Sheet.
1. The daemon ptpd can also run on other Blackfin chips. What is the precision achieved with ptpd on Blackfins other than BF518?
2. Is there any info available (App Notes, articles) showing the actual performance achieved on either BF518 or other Blackfins?
3. Are there any reference designs or examples available showing the usage of the pulse-per-second PPS output?
4. Is the PPS output available from chips other than BF518?
Thank you -- Wojtek
2011-07-17 23:16:06 Re: PTP on Blackfin Linux
Aaron Wu (CHINA)
1, this is the PTP on software, we don't test it
2, you can test it in your environment, here is how I do the test and my result:
On the master board
root:/> date -s 2010.03.16-15:30
root:/> ptpd -z linux_hw -f log.master
On the slave board
Tue Jun 5 05:07:07 UTC 2035
root:/> ptpd -z linux_hw -g -f log.slave
Tue Mar 16 15:32:37 UTC 2010
(ptpd debug) master-to-slave delay: 0s 44483ns
(ptpd debug) slave-to-master delay: 0s 56536ns
(ptpd debug) one-way delay: 0s 39828ns
(ptpd debug) offset from master: 0s 4900ns
4, it's part of the IEEE1588 engine module so no for other chips without this module.