RTI Control Registers
601
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Real-Time Interrupt (RTI) Module
17.3.7 RTI Compare Up Counter 0 Register (RTICPUC0)
The compare up counter 0 register holds the value to be compared with prescale counter 0 (RTIUC0).
This register is shown in
and described in
Figure 17-18. RTI Compare Up Counter 0 Register (RTICPUC0) [offset = 18h]
31
16
CPUC0
R/WP-0
15
0
CPUC0
R/WP-0
LEGEND: R/W = Read/Write; WP = Write in privileged mode only; -
n
= value after reset
Table 17-8. RTI Compare Up Counter 0 Register (RTICPUC0) Field Descriptions
Bit
Field
Value
Description
31-0
CPUC0
0-FFFF FFFFh
Compare up counter 0. This register holds the value that is compared with the up counter 0.
When the compare shows a match, the free running counter 0 (RTIFRC0) is incremented.
RTIUC0 is set to 0 when the counter value matches the RTICPUC0 value. The value set in this
register prescales the RTI clock.
If CPUC0 = 0, then
f
FRC0
= RTICLK/(2
32
+1) (Setting CPUC0 equal to 0 is not recommended. Doing so will hold the
Up Counter at 0 for 2 RTICLK cycles after it overflows from FFFF FFFFh to 0.)
If CPUC0
≠
0, then
f
FRC0
= RTICLK/(R1)
A read of this register returns the current compare value.
A write to this register:
• If TBEXT = 0, the compare value is updated.
• If TBEXT = 1, the compare value is unchanged.
17.3.8 RTI Capture Free Running Counter 0 Register (RTICAFRC0)
The capture free running counter 0 register holds the free running counter 0 on external events. This
register is shown in
and described in
Figure 17-19. RTI Capture Free Running Counter 0 Register (RTICAFRC0) [offset = 20h]
31
16
CAFRC0
R-0
15
0
CAFRC0
R-0
LEGEND: R = Read only; -
n
= value after reset
Table 17-9. RTI Capture Free Running Counter 0 Register (RTICAFRC0) Field Descriptions
Bit
Field
Value
Description
31-0
CAFRC0
0-FFFF FFFFh
Capture free running counter 0. This register captures the current value of the free running
counter 0 (RTIFRC0) when an event occurs, controlled by the external capture control block.
A read of this register returns the value of RTIFRC0 on a capture event.