I also struggled with that until I found that the CY8CKIT-062-BLE board has a 0-ohm resistor (R29) which shorts VBACKUP to P6_VDD. You have to remove this resistor to use a super-cap or backup battery.
Thank you for pointing that out. I've checked, and from what I can tell, the voltage from the capacitor does not get applied to the P6_VDD rail on my hardware. Also, the supercap does not seem to be draining particularly quickly, suggesting that the power side is most likely fine.
I originally misstated the board model that I have too. It's a Cy8CKIT-062-WiFi-BT. Sorry for the confusion, I've already spent quite a few hours trying to sort this out. I have edited my post accordingly.
Going through the schematic, I also couldn't finde any obvious place where V_BACKUP might get shorted into P6_VDD.
Maybe some more context on the perceived glitches:
I am trying to display some text and graphics on the CY8CKIT028-TFT display. With SW7 in VDDD position, the code works fine. With SW7 in Supercap position, I only get a very faded and corrupted image, even with the board connected via USB.
Sorry, my comments applied only to the CY8CKIT-062-BLE board not the Cy8CKIT-062-WiFi-BT.
Another interesting behavior that I'm observing is that the RTC also seems to reset when triggering an XRES through SW1.
From my understanding, this should not be the case as long as a sufficiently large voltage is available on V_BACKUP.
Table 18-5 in the reference manual states that the backup domain should remain on during an XRES assertion.
Steps to reproduce:
1. Set SW7 to SuperCap position (with supercap charged, confirmed via voltage reading across C19/C25: 1.6V)
2. Flash RTC basics example (with no alterations)
3. Set time via UART
4. Trigger XRES by pushing SW1
Expected behavior: Set time is retained
Observed behavior: Time restarts from Sat Jan 1 2000
I have the CY8CKIT-062-BLE and have found the supercap RTC support to be hardly useable. It works OK if I primarily leave the board powered on, and holds the clock if I briefly power it off. But, if it has been powered off for a few days, it will go into a boot loop if SW7 is in the supercap position and I try to power it on. Sometimes I can boot the board with SW7 in the VDDD/KITPROG2 and then switch it to supercap. Other times, switching 7 to the supercap position resets the board even after it is powered up. I assumed this was because the supercap was so discharged that it was pulling down the PSoC 6's power. But if yours is pre-charged, I can't explain that.