Rev. 1.0, 02/00, page 594 of 1141
Bit 3
FIFO2 Overwrite Flag (OVWB): If a write is attempted when the FIFO2 is full of the
timing pattern data and the output pattern data (FLB bit = 1), the write operation becomes invalid,
an interrupt is generated, the OVWB flag is set to 1, and the write data is lost. Wait until space
becomes available in the FIFO2, then write again.
Write 0 to clear the OVWB flag, because it is not cleared automatically.
Bit 3
OVWB
Description
0
Normal operation.
(Initial value)
1
Indicates that a write in FIFO2 was attempted when FIFO2 was full of data. Clear
this flag by writing 0 to this bit.
Bit 2
FIFO1 Overwrite Flag (OVWA): If a write is attempted when the FIFO1 is full of the
timing pattern data and the output pattern data (FLA bit = 1), the write operation becomes invalid,
an interrupt is generated, the OVWA flag is set to 1, and the write data is lost. Wait until space
becomes available in the FIFO1, then write again.
Write 0 to clear the OVWA flag, because it is not cleared automatically.
Bit 2
OVWA
Description
0
Normal operation.
(Initial value)
1
Indicates that a write in FIFO1 was attempted when FIFO1 was full. Clear this
flag by writing 0 to this bit.
Bit 1
FIFO2 Pointer Clear (CLRB): Clears the FIFO2 write position pointer. After 1 is
written, the bit immediately reverts to 0. Writing 0 in this bit has no effect.
Bit 1
CLRB
Description
0
Normal operation.
(Initial value)
1
Clears the FIFO2 pointer.
Bit 0
FIFO1 Pointer Clear (CLRA): Clears the FIFO1 write position pointer. After 1 is
written, the bit immediately reverts to 0. Writing 0 in this bit has no effect.
Bit 0
CLRA
Description
0
Normal operation
(Initial value)
1
Clears the FIFO1 pointer