DMTimer
20.1.5.10 TCRR Register (offset = 3Ch) [reset = 0h]
TCRR is shown in
and described in
The TCRR register is a 32-bit register, 16-bit addressable. The MCU can perform a 32-bit access or two
16-bit accesses to access the register . Note that since the OCP clock is completely asynchronous with
the timer clock, some synchronization is done in order to make sure that the TCRR value is not read while
it is being incremented. In 16-bit mode the following sequence must be followed to read the TCRR register
properly: First, perform an OCP Read Transaction to Read the lower 16-bit of the TCRR register (offset =
28h). When the TCRR is read and synchronized, the lower 16-bit LSBs are driven onto the output OCP
data bus and the upper 16-bit MSBs of the TCRR register are stored in a temporary register. Second,
perform an OCP Read Transaction to read the upper 16-bit of the TCRR register (offset = 2Ah). During
this Read, the value of the upper 16-bit MSBs that has been temporary register is forwarded onto the
output OCP data bus. So, to read the value of TCRR correctly, the first OCP read access has to be to the
lower 16-bit (offset = 28h), followed by OCP read access to the upper 16-bit (offset = 2Ah). As the TCRR
is updated using more sources (shadow_in_tcrr, incremented value of tcrr, TLDR and 0 ), a priority order
will be defined: The first priority is the OCP update. The second is the reload way (triggered through
TTGR reg. or following an auto-reload overflow). The third is the one-shot overflow reset to 0. The last is
the incremented value.
Figure 20-18. TCRR Register
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TIMER_COUNTER
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 20-20. TCRR Register Field Descriptions
Bit
Field
Type
Reset
Description
31-0
TIMER_COUNTER
R/W
0h
Value of TIMER counter
3577
SPRUH73H – October 2011 – Revised April 2013
Timers
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