1.3.2.3 Configuring Device Clock Domains (CLKCTL)
The CLKCTL register is used to choose between the available clock sources and also configure device behavior
during clock failure.
Figure 1-22. Clock Control (CLKCTL) Register
15
14
13
12
11
10
9
8
NMIRESETSEL XTALOSCOFF
XCLKINOFF
WDHALTI
INTOSC2HALTI INTOSC2OFF INTOSC1HALTI INTOSC1OFF
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
7
5
4
3
2
1
0
TMR2CLKPRESCALE
TMR2CLKSRCSEL
WDCLK
SRCSEL
OSCCLK
SRC2SEL
OSCCLK
SRCSEL
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 1-22. Clock Control (CLKCTL) Register Field Descriptions
Bit
Field
Value
Description
15
NMIRESETSEL
NMI Reset Select bit. This bit selects the action when the VCOCLK counter overflows due
to a missing clock condition.
0
MCLKRS is driven without any delay (default on reset)
1
NMI Watchdog Reset (NMIRS) initiates MCLKRS
Note:
The CLOCKFAIL signal is generated regardless of this mode selection.
14
XTALOSCOFF
Crystal Oscillator Off bit. This bit could be used to turn off the crystal oscillator if it is not
used.
0
Crystal oscillator on (default on reset)
1
Crystal oscillator off
13
XCLKINOFF
XCLKIN Off Bit: This bit turns external XCLKIN oscillator input off:
0
XCLKIN oscillator input on (default on reset)
1
XCLKIN oscillator input off
Note:
You need to select XCLKIN GPIO pin source via the XCLKINSEL bit in the XCLK
register. See the XCLK register description () for more details. XTALOSCOFF must be set
to 1, if XCLKIN is used.
12
WDHALTI
Watchdog HALT Mode Ignore bit. This bit selects if the watchdog is automatically turned off
by the HALT mode or not. This feature can be used to allow the selected watchdog clock
source to continue clocking the watchdog when HALT mode is active. This would enable
the watchdog to periodically wake up the device.
0
Watchdog automatically turned off by HALT (default on reset)
1
Watchdog continues to function in HALT mode.
11
INTOSC2HALTI
Internal Oscillator 2 HALT Mode Ignore bit. This bit selects if the internal oscillator 2 is
automatically turned off by the HALT mode or not. This feature can be used to allow the
internal oscillator to continue clocking when HALT mode is active. This would enable a
quicker wake-up from HALT.
0
Internal oscillator 2 automatically turned Off by HALT (default on reset)
1
Internal oscillator 2 continues to function in HALT mode. This feature can be used to allow
the internal oscillator to continue clocking when HALT mode is active. This would enable a
quicker wake-up from HALT.
10
INTOSC2OFF
Internal Oscillator 2 Off bit. This bit turns oscillator 2 off.
0
Internal oscillator 2 On (default on reset)
1
Internal oscillator 2 Off. This bit could be used by the user to turn off the internal oscillator 2
if it is not used. This selection is not affected by the missing clock detect circuit.
System Control and Interrupts
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
73
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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