MC68HC908AB32 Datasheet, PDF (197/392 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Timer Interface Module B (TIMB)
12.4 Pin Name Conventions
The TIMB share five I/O pins with port D and F I/O pins. The full name of
the TIMB I/O pin is listed in Table 12-1. The generic pin name appear in
the text that follows.
Table 12-1. Pin Name Conventions
TIMB Generic Pin Names:
TBCLK
TBCH0
TBCH1
TBCH2
TBCH3
Full TIMB Pin Names:
PTD4/TBCLK
PTF4/TBCH0
PTF5/TBCH1
PTF2/TBCH2
PTF3/TBCH3
12.5 Functional Description
Figure 12-1 shows the structure of the TIMB. The central component of
the TIMB is the 16-bit TIMB counter that can operate as a free-running
counter or a modulo up-counter. The TIMB counter provides the timing
reference for the input capture and output compare functions. The TIMB
counter modulo registers, TBMODH:TBMODL, control the modulo value
of the TIMB counter. Software can read the TIMB counter value at any
time without affecting the counting sequence.
The four TIMB channels are programmable independently as input
capture or output compare channels.
12.5.1 TIMB Counter Prescaler
The TIMB clock source can be one of the seven prescaler outputs or the
TIMB clock pin, PTD4/TBCLK. The prescaler generates seven clock
rates from the internal bus clock. The prescaler select bits, PS[2:0], in
the TIMB status and control register select the TIMB clock source.
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Timer Interface Module B (TIMB)
Technical Data
197