Tamas To achieve 10 microsecond resolution across multiple boxes would require a sync mechanism other than just ethernet packets arriving. PTP (Precision time protocol, I assume) or a GPS chip could keep the timing sync, and then a packet telling all boxes what time in the future to start.
BTW - it sounds like you are polling the ethernet input. I personally dislike polling when an interrupt is available. But you cannot rely on the timing of packets arriving. Marty -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of m_tamas Sent: Monday, May 14, 2012 3:36 AM To: [email protected] Subject: [lwip-users] raw lwIP on uC, timer or Ethernet Interrupt? Hi, I would like to develop an Ethernet device with an ARM uC. I am using a raw lwIP on it. Latter I would like to use more devices which are connected to a switch. A PC which is also connected to the switch will send a broadcast message which starts these devices. My problem is that the devices should start the working at the same time. The starting time difference between the devices should be under 10 uSec. Is it possible without PTP? Can you give me a development direction? My current example program work with a timer. The timer periodically 10ms trigger an Ethernet interrupt, but this 10 ms cause my starting problem. Can i use a simple Ethernet interrupt instead of timer? Best regards, Tamas -- View this message in context: http://old.nabble.com/raw-lwIP-on-uC%2C-timer-or-Ethernet-Interrupt--tp3 3827456p33827456.html Sent from the lwip-users mailing list archive at Nabble.com. _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
