High temperature and RCX

reference: LPCBARESDK-692

Status: Open

First reported: 6.0.14.1114

Fixed in: TBD

Description

This issue applies to applications configured in high temperature mode (CFG_HIGH_TEMPERATURE). Some combinations of crystal 32kHz and DA14585/DA14586 might fail to wake up within the expected time. This result in the next Bluetooth low energy event not being processed, therefore degraded Bluetooth performances.

This behavior is typically captured during development when an assert in the lld_sleep_compensate_func function of the rwble.c is raised.

if ((DEVELOPMENT_DEBUG) && (USE_POWER_OPTIMIZATIONS))
{
slp_period_retained = slp_period;
// if this Assertion hits then the LP ISR lasts longer than the time
// that has been reserved via LP_ISR_TIME_XTAL32_CYCLES and LP_ISR_TIME_USEC.
if (sleep_lp_cycles && (sleep_lp_cycles < slp_period))
ASSERT_WARNING(0);
}

Workaround

We recommend to be careful in selecting crystal parts and strictly abide by Renesas recommended crystal specification. We also recommend to be mindful of the potential issue during the design validation of the product.

When this issue appears, remediation will require specific crystal characterization and appropriate oscillator tuning. This is a complex procedure run by Renesas in house. Therefore, we would encourage you to contact your Renesas representative in order to obtain appropriate support.