z80180 ZiLOG Semiconductor, z80180 Datasheet - Page 68

• Manufacturer Part Number: z80180
• Description: Microprocessor Unit
• Manufacturer: ZiLOG Semiconductor

DMA I/O Address Register Channel 1B
DMA Status Register (DSTAT: I/O Address = 30h)
PS014004-1106
DMA I/O Address Register Channel 1B
DMA Status Register (DSTAT)
Bit
Mnemonic IAR1B (Address 2D)
DSTAT
also indicates DMA transfer status, in other words, completed or in progress.
Mnemonic DSTAT (Address 30)
DE1: DMA Enable Channel 1 (bit 7)—When
enabled. When a DMA transfer terminates (
When
made to the CPU.
To perform a software
WRITE
DE1
DE1
DE0: DMA Enable Channel 0 (bit 6)—When
enabled. When a DMA transfer terminates (
R/W
DE1
to
is cleared to
7
Figure 65. DMA Status Register (DSTAT: I/O Address = 30h)
DE1 = 0
1
is used to enable and disable DMA transfer and DMA termination interrupts.
access. Writing
enables channel 1 DMA and automatically sets
Figure 64. DMA I/O Address Register Channel 1B
R/W
DE0
6
and the DMA interrupt is enabled (
0
during
—
DWE1
W
5
3
WRITE
DE1
—
RESET
2
DWE0
to
W
—
4
to
0
DMA I/O Channel B Address
DE1
disables channel 1 DMA, but DMA is restartable. Writing
1
.
—
DIE1
R/W
,
DWE1
3
0
BCR1 = 0
BCR0 = 0
DIE0
R/W
must be written with
2
DIE1 = 1
DE1 = 1
DE0 = 1
),
),
1
DE1
DE0
DME
and
), a DMA interrupt request is
and
is reset to
is reset to
DME
(DMA Main Enable) to
DME = 1
DME = 1
R
0
0
during the same register
Microprocessor Unit
0
0
, channel 1 DMA is
, channel 0 DMA is
by the DMAC.
by the DMAC.
Architecture
Z80180
DSTAT
1
.
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