ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

trying a simplification to the math which computes RTC callback time.

pull/932/head
Rohit Grover 2015-03-16 13:45:33 +00:00
parent b20dc8e4d4
commit 71407656d2
1 changed files with 3 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c
View File

@ -223,16 +223,10 @@ void us_ticker_set_interrupt(timestamp_t timestamp)
* RTC_UNITS_TO_MICROSECONDS() converts this into microsecond units (in
* 64-bits). We then shave off the lower 32-bits of it and add in the
* incoming timestamp to get a mapping into a virtual 64-bit timestamp.
* There's one additional check to handle the case where the 32-bit callback
* timestamp is wrapped around--i.e. where the current time is near
* 0xFFFFFFFF, but incoming timestamp is near 0x00000000.
*/
uint64_t timestamp64 = (RTC_UNITS_TO_MICROSECONDS(rtc1_getCounter()) & ~(uint64_t)0xFFFFFFFF) + timestamp;
if ((us_ticker_read() > 0xF0000000) && (timestamp < 0x10000000)) {
timestamp64 += (uint64_t)0x100000000;
}
uint32_t newCallbackTime = MICROSECONDS_TO_RTC_UNITS(timestamp64);
const uint64_t currentTime64 = RTC_UNITS_TO_MICROSECONDS(rtc1_getCounter());
const uint64_t timestamp64 = currentTime64 + (timestamp - (timestamp_t)currentTime64);
uint32_t newCallbackTime = MICROSECONDS_TO_RTC_UNITS(timestamp64);
/* Check for repeat setup of an existing callback. This is actually not
* important; the following code should work even without this check. */