Texas Instruments TM4C1294NCPDT User Manual

Register 28: GPTM Clock Configuration (GPTMCC), offset 0xFC8
The GPTMCC register controls the clock source for the General-Purpose Timer module.
Note: When the ALTCLK bit is set in the GPTMCC register to enable using the alternate clock
source, the synchronization imposes restrictions on the starting count value (down-count),
terminal value (up-count) and the match value. This restriction applies to all modes of
operation. Each event must be spaced by 4 Timer (ALTCLK) clock periods + 2 system clock
periods. If some events do not meet this requirement, then it is possible that the timer block
may need to be reset for correct functionality to be restored.
Example: ALTCLK= T
PIOSC
= 62.5ns (16Mhz Trimmed)
T
hclk
= 1us (1Mhz)
4*62.5ns + 2*1us = 2.25us 2.25us/62.5ns = 36 or 0x23
The minimum values for the periodic or one-shot with a match interrupt enabled are:
GPTMTAMATCHR = 0x23 GPTMTAILR = 0x46
GPTM Clock Configuration (GPTMCC)
16/32-bit Timer 0 base: 0x4003.0000
16/32-bit Timer 1 base: 0x4003.1000
16/32-bit Timer 2 base: 0x4003.2000
16/32-bit Timer 3 base: 0x4003.3000
16/32-bit Timer 4 base: 0x4003.4000
16/32-bit Timer 5 base: 0x4003.5000
16/32-bit Timer 6 base: 0x400E.0000
16/32-bit Timer 7 base: 0x400E.1000
Offset 0xFC8
Type RW, reset 0x0000.0000
16171819202122232425262728293031
reserved
ROROROROROROROROROROROROROROROROType
0000000000000000Reset
0123456789101112131415
ALTCLKreserved
RWROROROROROROROROROROROROROROROType
0000000000000000Reset
DescriptionResetTypeNameBit/Field
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0x0000.0000ROreserved31:1
Alternate Clock Source
DescriptionValue
System clock (based on clock source and divisor factor
programmed in RSCLKCFG register in the System Control
Module)
0
Alternate clock source as defined by ALTCLKCFG register in
System Control Module.
1
0x0RWALTCLK0
1027June 18, 2014
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TM4C1294NCPDT Microcontroller

Texas Instruments TM4C1294NCPDT Specifications

General

Brand	Texas Instruments
Model	TM4C1294NCPDT
Category	Microcontrollers
Language	English