Not the PCM8523 time clock it is the PCF8563 losing time? - SOLVED

Hello, first I hope this is in the right selection. But I was wondering if anyone uses the pcm8523 real time clock module to lose more then 2 or 3 seconds at a time? I’m looking at this module to keep logging track and looking for one besides the ds3231 which I have used in the past.


Loosing 2-3 seconds over how long , an hour, week , year ?

The clock has a trim register to adjust accuracy or for external temperature compensation. As it stands I can’t see any built in temperature compensation and performance will depend on the quality of the Crystal you use.

Never used one and can’t find much detail on it .

The DS3231 is a very accurate , temperature compensated clock , in my experience , why not buy another?

If you want absolute accuracy look at getting time from an internet source

Post a link to the technical information on your pcm 8523 module, I could not find it although I found HMI interface and a motor controller. Also post a schematic of your circuit, not a frizzy picture. Answering hammy's questions will also help.

Hello, I was looking for a alternative to the DS3231. One I thought I came accross was the pcm8523, I was Wrong. That was the wrong about the module number. I had to look again the Real time and it is the PCF8563 I'm looking into. Here is the link.


That shows your project, not the part. I can understand your problem, they posted pictures but not a schematic. It is losing time because you have a 32kHz crystal, not a 32.768 kHz as the data sheet specifies. Change the crystal, it should work fine after that.

Hello, Yes the problem is the crystal is wrong. I got new crystals in today that seem to work better. I will check over the next 30 days to see if I lose anytime. I seem in the first month I was losing a second of time then by 2 months I was losing a toal of 3 seconds.

Edit: I will post a update in 30 days to see if that is the problem was the crystal.