problems with RTC

[Günther Brunner]

Hello,

I have a problem with the realtime clock RTC-72423 which should be
interfaced by a 68332 microcontroller (I know that is not an 8bit
controller, but maybe this is a general problem...).

The RTC is combined with the MCU via 4 data lines, 4 address lines, a
chip select and a read and a write line.

While reading from that RTC it happens, that it counts in
unpredictable steps. Sometimes I get a time being 15 sec. greater than
the previous time (interval reading, every 1 sec.) and sometimes the
time counts in 7 sec. steps - in short: it seems to be a random
number.
However when I set a breakpoint in my RTC-read routine, the memory
dump of the mapped RTC range shows the right values (every second is
counting in 1 second steps).

I don't know how to solve this problem. The support guy had no idea,
too.

Maybe one of you could help me...

Thanks in advance.

G.B.

 

[dont know]

Hello,

I have a problem with the realtime clock RTC-72423 which should be
interfaced by a 68332 microcontroller (I know that is not an 8bit
controller, but maybe this is a general problem...).

The RTC is combined with the MCU via 4 data lines, 4 address lines, a
chip select and a read and a write line.

While reading from that RTC it happens, that it counts in
unpredictable steps. Sometimes I get a time being 15 sec. greater than
the previous time (interval reading, every 1 sec.) and sometimes the
time counts in 7 sec. steps - in short: it seems to be a random
number.
However when I set a breakpoint in my RTC-read routine, the memory
dump of the mapped RTC range shows the right values (every second is
counting in 1 second steps).

I don't know how to solve this problem. The support guy had no idea,
too.

Maybe one of you could help me...

Thanks in advance.

G.B.

When you read the RTC on the fly are you waiting at least for a
ready-to-read state from the RTC? I dont think you can read the RTC
until it is updated internally (ready_to_read).