Xtal 32kHz may fail to start up at low temperature

ID: DA1459xSDK-767

Status: Fixed

First reported: 10.1.2.86

Fixed in: 10.1.4.104

Description

If the DA14592 FCQFN52 is used with an external 32kHz crystal, then it is possible that some devices will not start the 32 kHz oscillator at low temperature.

Workaround

Workaround 1: Replace line 174 in file sdk/bsp/peripherals/src/hw_sys_da1459x.c :

REG_SET_MASKED(CRG_TOP, CLK_XTAL32K_REG, 0x00001E7E, 0x00000E48);

with :

REG_SET_MASKED(CRG_TOP, CLK_XTAL32K_REG, 0x00001E7E, 0x00000E4E);

Patch file:

diff --git a/sdk/bsp/peripherals/src/hw_sys_da1459x.c b/sdk/bsp/peripherals/src/hw_sys_da1459x.c
index 3ebaf19..88763d6 100644
--- a/sdk/bsp/peripherals/src/hw_sys_da1459x.c
+++ b/sdk/bsp/peripherals/src/hw_sys_da1459x.c
@@ -171,7 +171,7 @@ void hw_sys_set_preferred_values(HW_PD pd)
         switch (pd) {
         case HW_PD_AON:
                 CRG_TOP->BIAS_VREF_SEL_REG = 0x0037;
-                REG_SET_MASKED(CRG_TOP, CLK_XTAL32K_REG, 0x00001E7E, 0x00000E48);
+                REG_SET_MASKED(CRG_TOP, CLK_XTAL32K_REG, 0x00001E7E, 0x00000E4E);
                 break;
         case HW_PD_SYS:
                 break;

Workaround 2: Use the internal RCX oscillator: Replace

#define dg_configUSE_LP_CLK     LP_CLK_32768

with

#define dg_configUSE_LP_CLK     LP_CLK_RCX