HMS87C5216 Datasheet, PDF (36/76 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER FOR UR(Universal Remocon) & WIRELESS KEYBOARD

HMS87C5216
12. Timer
12.1 Basic Interval Timer
The GMS81C5016/24/32 has one 8-bit Basic Interval Timer that
is free-run and can not stop. Block diagram is shown in Figure 12-
1.
The Basic Interval Timer generates the time base for key scan-
ning, watchdog timer counting, and etc. It also provides a Basic
interval timer interrupt (IFBIT). As the count overflow from FF_H
to 00_H, this overflow causes the interrupt to be generated.
-8bit binary counter
-Use the bit output of prescaler as input to secure the oscillation
stabilization time after power-on
-Secures the oscillation stabilization time in standby mode (stop
mode) release
-Contents of B.I.T can be read
-Provides the clock for watch dog timer.
DATA BUS
-
-
WDTON ENPCK BTCL
BTS2
BTS1
BTS0 _CKCTLR
PS3
PS4
PS5
PS6
PS7
PS8
PS9
PS10
MUX
BIT0
BIT1
BIT2
BIT3
BIT4
BIT5
BIT6
BITR
BIT7
IFBIT
DATA BUS
Figure 12-1 Block Diagram of Basic Interval Timer
(1) Control of B.I.T
The Basic Interval Timer is controlled by the clock control regis-
ter (CKCTLR) shown in Figure 12-2. If bit3(BTCL) of CKCTLR
is set to ``1``, B.I.T is cleared, and then, after one machine cycle,
BTCL becomes ``0``, and B.I.T starts counting. BTCL is set to
``0`` in reset state.
SEP. 2004 Ver 1.01