230 HITACHI
10.2.4
Timer Function Control Register (TFCR)
The timer function control register (TFCR) is an 8-bit read/write register that selects
complementary PWM/reset-synchronized PWM for channels 3 and 4 and sets the buffer operation.
TFCR is initialized on a reset or standby mode to H'C0 or H'40.
Bit:
7
6
5
4
3
2
1
0
Bit name:
—
—
CMD1
CMD0
BFB4
BFA4
BFB3
BFA3
Initial value:
*
1
—
0
0
0
0
0
0
R/W:
—
R/W
R/W
R/W
R/W
R/W
R/W
Note:
Undefined
Bits 7 and 6 (reserved): Bit 7 is read as undefined. Bit 6 is always read as 1. The write value to
bit 7 should be 0 or 1. The write value to bit 6 should always be 1.
Bits 5 and 4 (combination mode 1 and 0 (CMD1 and CMD0)): CMD1 and CMD0 select the
complementary PWM mode or reset-synchronized mode for channels 3 and 4. Set the
complementary PWM/reset-synchronized PWM mode while the timer counter (TCNT) being
used is off. When these bits are used to set the complementary PWM/reset-synchronized PWM
mode, they take priority over the PWM4 and PWM3 bits of the TMDR. While the
complementary PWM/reset-synchronized PWM mode settings and the SYNC4 and SYNC3 bit
settings of the timer synchro register (TSNC) are valid simultaneously, when the
complementary PWM mode is set, channels 3 and 4 should not be set to operate
simultaneously (SYNC 4 and SYNC 3 bits of TSNC should not both be set to 1).
Bit 5: CMD1
Bit 4: CMD0
Description
0
0
Channels 3 and 4 operate normally (initial value)
1
Channels 3 and 4 operate normally
1
0
Channels 3 and 4 operate together in complementary PWM
mode
1
Channels 3 and 4 operate together in reset-synchronized
PWM mode
Bit 3 (buffer mode B4 (BFB4)): BFB4 selects the buffer mode for GRB4 and BRB4 in channel
4.
Bit 3: BFB4
Description
0
GRB4 operates normally in channel 4 (initial value)
1
GRB4 and BRB4 operate in buffer mode in channel 4