Datasheet

Timebase Module (TBM)
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
260 Freescale Semiconductor
Figure 17-1. Timebase Block Diagram
17.5 TBM Interrupt Rate
The interrupt rate is determined by the equation:
where:
f
CGMXCLK
=Frequency supplied from the clock generator (CGM) module
Divider = Divider value as determined by TBR2–TBR0 settings and TMBCLKSEL, see Table 17-1
÷ 2 ÷ 2 ÷ 2 ÷ 2
÷ 2 ÷ 2
÷ 2
÷ 2 ÷ 2 ÷ 2 ÷ 2 ÷ 2 ÷ 2 ÷ 2
SEL
0 0 0
0 0 1
0 1 0
0 1 1
TBIF
TBR1 TBR0
TBIE
TBMINT
TBON
÷ 2
R
TACK
TBR2
1 0 0
1 0 1
1 1 0
1 1 1
TBMCLK
FROM CGM MODULE
TMBCLKSEL
FROM CONFIG2
DIVIDE BY 128
PRESCALER
0
1
CGMXCLK
t
TBMRATE
=
Divider
f
CGMXCLK