Descriptions Of Respective Registers; Timer Mode Register A (Tma) - Renesas Hitachi H8S/2194 Series Hardware Manual

12.2

Descriptions of Respective Registers

12.2.1

Timer Mode Register A (TMA)

Bit :
TMAOV
Initial value :
R/(W) *
R/W :
Note: * Only 0 can be written to clear the flag.
The timer mode register A (TMA) works to control the interrupts of the Timer A and to select
the input clock.
TMA is an 8-bit read/write register. When reset, the TMA will be initialized to H'30.
Bit 7: Timer A Overflow Flag (TMAOV)
This is a status flag indicating the fact that the TCA is overflowing (H'FF → H'00).
Bit 7
TMAOV Description
0 [Clearing conditions]
When 0 is written to the TMAOV flag after reading the TMAOV flag under the status
where TMAOV = 1
1 [Setting conditions]
When the TCA overflows
Bit 6: Enabling Interrupt of the Timer A (TMAIE)
This bit works to permit/prohibit occurrence of interrupt of the Timer A (TMAI) when the TCA
overflows and when the TMAOV of the TMA is set to 1.
Bit 6
TMAIE Description
0 Prohibits occurrence of interrupt of the Timer A (TMAI)
1 Permits occurrence of interrupt of the Timer A (TMAI)
Bits 5 and 4: Reserved
When they are read, 1 will always be readout. Writes are disabled.
7 6 5
TMAIE —
0 0 1
—
R/W
4 3 2
— TMA3 TMA2
1 0 0
—
R/W R/W
Rev. 2.0, 11/00, page 291 of 1037
1 0
TMA1 TMA0
0 0
R/W R/W
(Initial value)
(Initial value)