Sharp MZ-5500 - Page 84

*Mode, 00, 01, 10, 11, has function to select the internal register and RAM
banks which can be achieved by writing the select data in the mode register.
Since mode registers are assigned to the same address, it can be revised
under any mode.
MODE register (A3, A2, Al, AO)
(1,1,0,1)
D
D3 D2 Dl
DO
Timer Alarm
EN EN
MI
MO
1
1
0 0 MODEOO: Set or read time.
0
1
MODEOI :
Set or read alarm,
12/24 hours,
leap
year.
1
0
Write or read RAM
BLOCKiO.
1 1
Write ore ad RAM
BLOCKli.
1: Alarm output enable.
0: Alarm output disable (16Hz and 1Hz signals
are disregarded).
~ ------ ------ ------ ---- ----~ 1: Timer to start.
0: Counte~ stops after this.
*Leap year counter:
Leap year when D1=DO=0. Counted up at the same time the year is counted.
*12/2
l
l hours selector:
The 24 hours system is adopted when DO=l. The I
t
hours system is adopted
when DO=O. With Dl=l, PM is selected. With D1=0, AM is selected.
*Reset controller:
16Hz/lHzCK register
CA3, A2, Al, AO)=(l,l,l,l)=F
All alarm registers are reset with DO=l.
Minutes above seconds are reset with D1=1.
16HzCK pulse is ON with D2=0.
1HzCK pulse is ON with D3=0.
*Addre , ss 0 - D
Read
and write are possible.
d
*Address E - F
Only write is possible.
*The following are provided for the real time clock related IOCS modul e . anrl
can be used when called as a subroutine by the machine languag e . For c!,'uli I,
refer to Section 3, Software.
IOCS name Function
TIMRD
Reacls the real time clock.
TU1SET
Sets the real time clock.
ONTIM
Enables the alarm interrupt.
I
j
OFFTIM
Disables the alarminj: _ e!rupt. !
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