MC68HC908KX8 Datasheet, PDF (218/310 Pages) Motorola, Inc – Microcontrollers

Timebase Module (TBM)
15.6 TBM Interrupt Rate
The interrupt rate is determined by the equation:
t_TBMRATE = -f-_T----_B---_M----1-_R----_A---_T----_E- = _f--DT----_B-i-v-_M---i-d-_C---e-_L---r_K-
where:
f_TBMCLK = Frequency supplied from the internal clock
generator (ICG) module
Divider = Divider value as determined by TBR2–TBR0
settings. See Table 15-1.
As an example, a clock source of 4.9152 MHz and the TBR2–TBR0 set
to {011}, the divider tap is 128 and the interrupt rate calculates to
128/4.9152 x 10⁶ = 26 µs.
Table 15-1. Timebase Divider Selection
TBR2
0
0
0
0
1
1
1
1
TBR1
0
0
1
1
0
0
1
1
TBR0
0
1
0
1
0
1
0
1
Divider Tap
32768
8192
2048
128
64
32
16
8
NOTE: Do not change TBR2–TBR0 bits while the timebase is enabled
(TBON = 1).
Technical Data
218
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
Timebase Module (TBM)
MOTOROLA