Writing to RTC time registers causes a delay in code execution.

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Alaric on Tue Jul 23 00:13:53 MST 2013
I have come across a problem (to us) with the rtc on the MCB1800 (lpc1850) development board (and also
our board). The problem occurs when 2 rtc time writes are performed back-to-back.

What seems to happen is if a second write to rtc time registers is performed without a delay
(no less than ~900msec) then code execution, includes interrupts, is halted for 300-800msecs. I
know the rtc uses a 1Hz clock and rtc register access uses the CLK_M3_BUS so register updates
takes a few clock cycles but surely it shouldn't halt code execution on the processor?

Reads from the rtc are not effected even after a write to rtc.
I've included a modified blinky example application that shows the problem.

Has anyone else encountered this problem on the LPC18xx?

Original Attachment has been moved to: Blinky_0.zip