M41T82 datasheet(22/58 Pages) STMICROELECTRONICS

22 / 58 page

Clock operation

M41T82 M41T83

22/58

3.2

Clock/control register map

The M41T8x offers 32 internal registers which contain clock, calibration (digital and analog),

Alarm 1 and 2, Watchdog, Flags, Timer, and Square Wave (M41T83 only). The clock

registers are memory locations which contain external (user accessible) and internal copies

of the data (usually referred to as BiPORT™ TIMEKEEPER® cells). The external copies are

independent of internal functions except that they are updated periodically by the

simultaneous transfer of the incremented internal copy. The internal divider (or clock) chain

will be reset upon the completion of a WRITE to any clock address (00h to 07h). The

system-to-user transfer of clock data will be halted whenever the address being read is a

clock address (00h to 07h). The update will resume either due to a Stop Condition or when

the pointer increments to a non-clock address. Clock and alarm registers store data in BCD

format. Calibration, Timer, Watchdog, and Square Wave bits are written in a binary format.

M41T82 Arkusz danych(PDF) 22 Page - STMicroelectronics