Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
226 Timer Interface B (TIMB) MOTOROLA
Timer Interface B (TIMB)
12.2 IntroductionThis section describes the timer interface module B (TIMB). The TIMB is
a 2-channel timer that provides:
• Timing reference with input capture
• Output compare
• Pulse-width modulation functions
Figure 12-1 is a block diagram of the TIMB.
NOTE: The TIMB module is not available in the 56-pin shrink dual in-line
package (SDIP).
12.3 FeaturesFeatures of the TIMB include:
• Two input capture/output compare channels:
– Rising-edge, falling-edge, or any-edg e input capture trigger
– Set, clear, or toggle output compare action
• Buffered and unbuffered pulse-width modulation (PWM) signal
generation
• Programmable TIMB clock input:
– 7-frequency internal bus clock prescaler selection
– External TIMB clock input (4-MHz maximum frequency)
• Free-running or modulo up-count op eration
• Toggle any channel pin on overflo w
• TIMB counter stop and reset bits
12.4 Functional DescriptionFigure 12-1 shows the TIMB structure. 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 com pare functions. Th e 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.