Maxim Integrated 12-2
MAX31782 User’s Guide
Revision 0; 8/11
SECTION 12: TIMER B MODULE
The MAX31782 provides one Timer B module that can be configured to provide different timer, counter, clock, or PWM
functions. The Timer B uses the TBB and TBA pins, which are also used for JTAG and GPIO operation. Table 12-1
details these pins.
Table 12-1. Timer B Pins
Table 12-2. Timer B Mode Summary
12.1 Detailed Description
The Timer B is a 16-bit programmable module that supports input clock prescaling and set/reset/toggle PWM output
control functionality. Another distinguishing characteristic of Timer B is that its count ranges from 0000h to the value
stored in the 16-bit capture/reload register (TBR) instead of FFFFh as in some timers.
The possible Timer B operating modes and related control bits are shown in Table 12-2. A complete description of each
mode is contained in the subsequent sections.
All timer operation and functionality is set using the Timer B control register, TB0CN. Three other registers are used to
hold the current timer/counter value (TB0V), the capture/reload value (TB0R), and a compare value (TB0C).
In all modes of operation, the timer is enabled by setting the Timer B run control bit (TRB) in the Timer B control register
to 1. If this bit is cleared to 0 (reset default condition), no timer activity is possible.
When the Timer B is operated as a timer (i.e., it counts scaled system clocks), the TBPS[2:0] bits in the timer control
register determine the factor by which the active system clock is divided (prescaled) before being counted by the timer.
Other relevant control bits are described in the following mode descriptions. A complete listing of the Timer B registers
and bits with their effects on timer operation are given in 12.2 Timer B Register Descriptions.
The Timer B pins, TBA and TBB, are used for GPIO and JTAG, respectively, by default. The Timer B functionality of
these pins is enabled through the TB0CN register. The following sections detail the TB0CN configurations required
depending on the desired Timer B function. To use the TBB pin, the JTAG port must also be disabled by setting the
TAP bit in the SC register to 0.
TIMER B PIN MAX31782 PIN NUMBER GPIO PIN JTAG PIN
TBA 33 P6.4 —
TBB 35
P6.2 TMS
TIMER B OPERATIONAL
MODE
TB0CN REGISTER BIT SETTINGS
TBCS:TBCR TBOE DCEN EXENB
C/TB CP/RLB
OPTIONAL CONTROL
Auto-Reload 00 0 0 0 X 0
Auto-Reload Using TBB Pin 00 0 0 1 X 0
Capture Using TBB Pin 00 0 0 1 X 1
Up/Down Count Using TBB Pin 00 0 1 0 X 0
Up-Count PWM/Output Control ≠00 X 0 X X 0
Up/Down PWM/Output Control ≠00 X 1 X X 0
— — 0 X X 1 X Input Clock = TBA Pin
Clock Output on TBA Pin — 1 X X 0 0
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