nvSRAM with disabled RTC function

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello,

Customers are considering replacing current parts with new parts.

1) The CY14B116M has an RTC function, but this function will be not used.
The following pins are not wired on the customer's existing board and will be open.
  INT, Xout, Xin, V_RTcap, V_RTbat

I believe it is correct way when RTC function is not used on this device.


2) CY14B116M has an RTC Register.
What will happen as a device if a write operation is performed on this register?
Since there is no status pin, the write transaction seems to have completed normally from the host, and I understand that if I read it, I can read the RTC register. Is this correct?

MPN:
CY14B116N-ZSP45XI: Now in use
CY14B116M-ZSP25XI: Under consideration

Best Regards,

Naoaki Morimoto

0 Likes
1 Solution
PradiptaB_11
Moderator
Moderator
Moderator
500 replies posted 250 solutions authored 250 replies posted

Hi Morimoto-san,

Please find my comments below.

1. When you are not using the RTC functionality in an nvSRAM with RTC, the RTC-related pins of the part (XIN, XOUT, VRTCcap, and VRTCbat) must be left floating as already you have pointed out.  Also, you must ensure that the RTC oscillator is disabled by setting the OSCEN bit  to ‘1’ and performing a software store after tRTCp. 

2. When not using the RTC feature the last 16 address used for RTC registers do not have any utility. You may write to bits which are writable in the register and later read them but from any application point of view it does not add value to the application. All the register you will read will not have the correct data and when you are disabling the RTC feature it is suggested to leave out the RTC register addresses from any form of manipulation.(R/W)

Thanks,

Pradipta.

View solution in original post

0 Likes
4 Replies