HD6432646 Hitachi, HD6432646 Datasheet - Page 385

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

10.4.5
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 upon overflow/underflow
of TCNT2 (TCNT5) as set in bits TPSC2 to TPSC0 in TCR.
Underflow occurs only when the lower 16-bit TCNT is in phase-counting mode.
Table 10-6 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
Table 10-6 Cascaded Combinations
Combination
Channels 1 and 2
Channels 4 and 5
Example of Cascaded Operation Setting Procedure: Figure 10-21 shows an example of the
setting procedure for cascaded operation.
and the counter operates independently in phase counting mode.
<Cascaded operation>
Cascaded operation
Cascaded Operation
Set cascading
Start count
Figure 10-21 Cascaded Operation Setting Procedure
Upper 16 Bits
TCNT1
TCNT4
[1]
[2]
[1] Set bits TPSC2 to TPSC0 in the channel 1
[2] Set the CST bit in TSTR for the upper and lower
(channel 4) TCR to B’111 to select TCNT2
(TCNT5) overflow/underflow counting.
channel to 1 to start the count operation.
Lower 16 Bits
TCNT2
TCNT5
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