TM4C1233H6PZIR Datasheet, PDF (694/1233 Pages) Texas Instruments – Tiva TM4C1233H6PZ Microcontroller

General-Purpose Timers
The following table shows a variety of configurations for a 16-bit free-running timer while using the
prescaler. All values assume an 80-MHz clock with Tc=12.5 ns (clock period). The prescaler can
only be used when a 16/32-bit timer is configured in 16-bit mode and when a 32/64-bit timer is
configured in 32-bit mode.
Table 11-5. 16-Bit Timer With Prescaler Configurations
Prescale (8-bit value)
# of Timer Clocks (Tc)^a
00000000
1
00000001
2
00000010
3
------------
--
11111101
254
11111110
255
11111111
256
a. Tc is the clock period.
Max Time
0.8192
1.6384
2.4576
--
208.0768
208.896
209.7152
Units
ms
ms
ms
--
ms
ms
ms
The following table shows a variety of configurations for a 32-bit free-running timer using the prescaler
while configured in 32/64-bit mode. All values assume an 80-MHz clock with Tc=12.5 ns (clock
period).
Table 11-6. 32-Bit Timer (configured in 32/64-bit mode) With Prescaler Configurations
Prescale (16-bit value)
# of Timer Clocks (Tc)^a
Max Time
Units
0x0000
1
53.687
s
0x0001
2
107.374
s
0x0002
3
214.748
s
------------
0xFFFD
0xFFFE
0xFFFF
--
65534
65535
65536
--
0.879
1.759
3.518
--
10⁶ s
10⁶ s
10⁶ s
a. Tc is the clock period.
11.3.2.2
Real-Time Clock Timer Mode
In Real-Time Clock (RTC) mode, the concatenated versions of the Timer A and Timer B registers
are configured as an up-counter. When RTC mode is selected for the first time after reset, the
counter is loaded with a value of 0x1. All subsequent load values must be written to the GPTM
Timer n Interval Load (GPTMTnILR) registers (see page 739). If the GPTMTnILR register is loaded
with a new value, the counter begins counting at that value and rolls over at the fixed value of
0xFFFFFFFF. Table 11-7 on page 694 shows the values that are loaded into the timer registers when
the timer is enabled.
Table 11-7. Counter Values When the Timer is Enabled in RTC Mode
Register
GPTMTnR
GPTMTnV
GPTMTnPS
GPTMTnPV
Count Down Mode
Not available
Not available
Not available
Not available
Count Up Mode
0x1
0x1
Not available
Not available
694
July 17, 2013
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