Datasheet

Section 10 16-Bit Timer Pulse Unit (TPU)
Rev.6.00 Mar. 18, 2009 Page 452 of 980
REJ09B0050-0600
10.4.4 Cascaded Operation
In cascaded operation, two 16-bit counters for different channels are used together as a 32-bit
counter.
This function works by counting the channel 1 (channel 4) counter clock at overflow/underflow of
TCNT_2 (TCNT_5) as set in bits TPSC2 to TPSC0 in TCR.
Underflow occurs only when the lower 16-bit TCNT is in phase counting mode.
Table 10.29 shows the register combinations used in cascaded operation.
Note: When phase counting mode is set for channel 1 or 4, the counter clock setting is invalid
and the counter operates independently in phase counting mode.
Table 10.29 Cascaded Combinations
Combination Upper 16 Bits Lower 16 Bits
Channels 1 and 2 TCNT_1 TCNT_2
Channels 4 and 5 TCNT_4 TCNT_5
Example of Cascaded Operation Setting Procedure: Figure 10.17 shows an example of the
setting procedure for cascaded operation.
Cascaded operation
Set cascading
Start count
<Cascaded operation>
Set bits TPSC2 to TPSC0 in the channel 1
(channel 4) TCR to B'1111 to select TCNT_2
(TCNT_5) overflow/underflow counting.
Set the CST bit in TSTR for the upper and lower
channel to 1 to start the count operation.
[1]
[2]
[1]
[2]
Figure 10.17 Cascaded Operation Setting Procedure