TMP86FM48 Datasheet, PDF (61/205 Pages) Toshiba Semiconductor – 8 Bit Microcontroller

TMP86FM48
2.3 Time Base Timer (TBT)
The time base timer generates time base for key scanning, dynamic displaying, etc. It also
provides a time base timer interrupt (INTTBT).
An INTTBT is generated on the first falling edge of source clock (The divider output of the
timing generator) after the time base timer has been enabled. The divider is not cleared by the
program; therefore, only the first interrupt may be generated ahead of the set interrupt period
(Figure 2.3.1 (b)).
The interrupt frequency (TBTCK) must be selected with the time base timer disabled (the
interrupt frequency must not be changed with the disable from the enable state). Both
frequency selection and enabling can be performed simultaneously.
fc/2²³ or fs/2¹⁵
fc/2²¹ or fs/2¹³
fc/2¹⁶ or fs/2⁸
fc/2¹⁴ or fs/2⁶
fc/2¹³ or fs/2⁵
fc/2¹² or fs/2⁴
fc/2¹¹ or fs/2³
fc/2⁹ or fs/2
MPX
A
B
C
D
E
Y
F
G
HS
3
Source clock
Falling edge
detector
TBTCK
TBTEN
TBTCR
Time base timer control register
(a) Configuration
IDLE0/SLEEP0
release request
INTTBT
interrupt request
Source clock
TBTEN
INTTBT
Interrupt period
Enable TBT
(b) Time base timer interrupt
MPX: Multiplexer
Figure 2.3.1 Time Base Timer
Example: Sets the time base timer frequency to fc/2¹⁶ [Hz] and enables an INTTBT interrupt.
LD
(TBTCR), 00000010B
; TBTCK ← 010
LD
(TBTCR), 00001010B
; TBTEN ← 1
DI
; IMF ← 0
SET
(EIRL). 6
86FM48-59
2007-08-24