HITACHI 241
Bit:
7
6
5
4
3
2
1
0
Bit name:
—
—
—
—
—
OVIE
IMIEB
IMIEA
Initial value:
*
1
—
1
—
1
—
1
—
0
0
0
R/W:
—
R/W
R/W
R/W
Note:
Undefined
Bits 7–3 (reserved): Bit 7 is read as undefined. Bits 6–3 are always read as 1. The write value
to bit 7 should be 0 or 1. The write value to bits 6–3 should always be 1.
Bit 2 (overflow interrupt enable (OVIE)): When the TSR overflow flag (OVF) is set to 1,
OVIE enables or disables interrupt requests from the OVF.
Bit 2: OVIE
Description
0
Disables interrupt requests by the OVF (initial value)
1
Enables interrupt requests from the OVF
Bit 1 (input capture/compare match interrupt enable B (IMIEB)): When the IMFB bit of the
TSR is set to 1, IMIEB enables or disables the interrupt requests from the IMFB.
Bit 1: IMIEB
Description
0
Disables interrupt requests by the IMFB (IMIB) (initial value)
1
Enables interrupt requests from the IMFB (IMIB)
Bit 0 (input capture/compare match interrupt enable A (IMIEA)): When the IMFA bit of the
TSR is set to 1, IMIEA enables or disables the interrupt requests from the IMFA.
Bit 0: IMIEA
Description
0
Disables interrupt requests by the IMFA (IMIA) (initial value)
1
Enables interrupt requests from the IMFA (IMIA)
10.3
CPU Interface
10.3.1
16-Bit Accessible Registers
The timer counters (TCNT), general registers A and B (GRA, GRB), and buffer registers A and B
(BRA, BRB) are 16-bit registers. The SH CPU can access these registers a word at a time using a
16-bit data bus. Byte access is also possible. Read and write operations performed on the TCNT in
word units are shown in figures 10.6 and 10.7. Byte-unit read and write operations on TCNTH and
TCNTL are shown in figures 10.8–10.11.