SH7108 Datasheet, PDF (214/560 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 8 Multifunction Timer Pulse Unit (MTU)
Phase Counting Mode Application Example: Figure 8.29 shows an example in which channel 1
is in phase counting mode, and channel 1 is coupled with channel 0 to input servo motor 2-phase
encoder pulses in order to detect position or speed.
Channel 1 is set to phase counting mode 1, and the encoder pulse A-phase and B-phase are input
to TCLKA and TCLKB.
Channel 0 operates with TCNT counter clearing by TGRC_0 compare match; TGRA_0 and
TGRC_0 are used for the compare match function and are set with the speed control period and
position control period. TGRB_0 is used for input capture, with TGRB_0 and TGRD_0 operating
in buffer mode. The channel 1 counter input clock is designated as the TGRB_0 input capture
source, and the pulse widths of 2-phase encoder 4-multiplication pulses are detected.
TGRA_1 and TGRB_1 for channel 1 are designated for input capture, and channel 0 TGRA_0 and
TGRC_0 compare matches are selected as the input capture source and store the up/down-counter
values for the control periods.
This procedure enables the accurate detection of position and speed.
TCLKA
TCLKB
Edge
detection
circuit
Channel 1
TCNT_1
TGRA_1
(speed period capture)
TGRB_1
(position period capture)
TCNT_0
TGRA_0
+
(speed control period)
-
TGRC_0
+
(position control period)
-
TGRB_0 (pulse width capture)
TGRD_0 (buffer operation)
Channel 0
Figure 8.29 Phase Counting Mode Application Example
Rev.1.00 Sep. 18, 2008 Page 180 of 522
REJ09B0069-0100