HD6417144 RENESAS [Renesas Technology Corp], HD6417144 Datasheet - Page 320

• Manufacturer Part Number: HD6417144
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

11.
11.4.6
In phase counting mode, the phase difference between two external clock inputs is detected and
TCNT is incremented/decremented accordingly. This mode can be set for channels 1 and 2.
When phase counting mode is set, an external clock is selected as the counter input clock and
TCNT operates as an up/down-counter regardless of the setting of bits TPSC0 to TPSC2 and bits
CKEG0 and CKEG1 in TCR. However, the functions of bits CCLR0 and CCLR1 in TCR, and of
TIOR, TIER, and TGR, are valid, and input capture/compare match and interrupt functions can be
used.
This can be used for two-phase encoder pulse input.
If overflow occurs when TCNT is counting up, the TCFV flag in TSR is set; if underflow occurs
when TCNT is counting down, the TCFU flag is set.
The TCFD bit in TSR is the count direction flag. Reading the TCFD flag reveals whether TCNT is
counting up or down.
Table 11.32 shows the correspondence between external clock pins and channels.
Table 11.32 Phase Counting Mode Clock Input Pins
Example of Phase Counting Mode Setting Procedure: Figure 11.24 shows an example of the
phase counting mode setting procedure.
Rev.4.00 Mar. 27, 2008 Page 276 of 882
REJ09B0108-0400
Channels
When channel 1 is set to phase counting mode
When channel 2 is set to phase counting mode
Multi-Function Timer Pulse Unit (MTU)
Phase Counting Mode
Figure 11.24
<Phase counting mode>
Select phase counting
Phase counting mode
Start count
mode
Example of Phase Counting Mode Setting Procedure
[1]
[2]
[1] Select phase counting mode with bits
[2] Set the CST bit in TSTR to 1 to start
MD3 to MD0 in TMDR.
the count operation.
A-Phase
TCLKA
TCLKC
External Clock Pins
B-Phase
TCLKB
TCLKD