This is the mail archive of the ecos-patches@sourceware.org mailing list for the eCos project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
As i said in my last email, the AT91 system controller has a different watchdog timer than the older devices. This patch contains a driver for this new hardware. A couple of points to note: 1) The watchdog timer is driven by the slow clock of the AT91. This is an LC oscillator on the chip. The accuracy of this oscillator is dependent on silicon process at manufacturing time and the temperature. I found that my development board a watchdog timeout of 1000ms actually goes off at around 550ms at room temperature. So be generous with your timeouts. This also means that one of the test case fails because the timer goes off too early. 2) The mode register on the watchdog is read/write once. So once the watchdog has been configured it cannot be changed without a reset. It is possible if you are using Redboot it disables the watchdog and so the application cannot then use it. Similarly a JTAG debugger could disable it. I've put in an assertion check to detect this condition, so if the watchdog does not appear to be working enable INFRA_DEBUG and see if the assertion goes off. Andrew
Attachment:
devs.watchdog.arm.at91wdtc.diff
Description: Text document
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |