Datasheet

Tick counter
Trigger signal
Counter reload
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27.3.31 Tick Count Register (TICKCNT)
One of the trigger sources for TGs is an internal periodic time trigger. This time trigger is called a tick
counter and is basically a down-counter with a preload/reload value. Every time the tick counter detects an
underflow it reloads the initial value and toggles the trigger signal provided to the TGs.
The trigger signal, shown in Figure 27-66 as a square wave, illustrates the different trigger event types for
the TGs (for example, rising edge, falling edge, and both edges).
Figure 27-66. Tick Counter Operation
This register is shown in Figure 27-67 and described in Table 27-39.
Figure 27-67. Tick Count Register (TICKCNT) [offset = 90h]
31 30 29 28 27 16
TICKENA RELOAD CLKCTRL Reserved
R/W-0 R/S-0 R/W-0 R-0
15 0
TICKVALUE
R/W-0
LEGEND: R = Read only; R/W = Read/Write; S = Set; -n = value after reset
Table 27-39. Tick Count Register (TICKCNT) Field Descriptions
Bit Field Value Description
31 TICKENA Tick counter enable.
0 The internal tick counter is disabled. The counter value remains unchanged.
Note: When the tick counter is disabled, the trigger signal is forced low.
1 The internal tick counter is enabled and is clocked by the clock source selected by CLKCTRL[1:0].
When the tick counter is enabled it starts down-counting from its current value. When TICKENA
goes from 0 to 1, the tick counter is automatically loaded with the contents of TICKVALUE.
30 RELOAD Pre-load the tick counter. RELOAD is a set-only bit; writing a 1 reloads the tick counter with the
value stored in TICKVALUE. Reading RELOAD always returns a 0.
Note: When the tick counter is reloaded by the RELOAD bit, the trigger signal is not
toggled.
29-28 CLKCTRL Tick counter clock source control. CLKCTRL defines the clock source that is used to clock the
internal tick counter.
0 SPICLK of data word format 0 is selected as the clock source of the tick counter
1h SPICLK of data word format 1 is selected as the clock source of the tick counter
2h SPICLK of data word format 2 is selected as the clock source of the tick counter
3h SPICLK of data word format 3 is selected as the clock source of the tick counter
27-16 Reserved 0 Read returns 0. Writes have no effect.
15-0 TICKVALUE 0-FFFFh Initial value for the tick counter. TICKVALUE stores the initial value for the tick counter. The tick
counter is loaded with the contents of TICKVALUE every time an underflow condition occurs and
every time the RELOAD flag is set by the host.
1303
SPNU562–May 2014 Multi-Buffered Serial Peripheral Interface Module (MibSPI) with Parallel Pin
Option (MibSPIP)
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