STPC4EDBC STMICROELECTRONICS [STMicroelectronics], STPC4EDBC Datasheet - Page 72

• Manufacturer Part Number: STPC4EDBC
• Description: X86 Core PC Compatible Information Appliance System-on-Chip
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

DESIGN GUIDELINES
The
implementation of the external glue logic for DMA
Request time-multiplexing and DMA Acknowledge
demultiplexing. Like for the interrupt lines, this
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ISA, Refresh
ISA, PIO
ISA, FDC
ISA, PIO
Slave DMAC
ISA
ISA
ISA
figure
below
Figure 6-11. Typical DMA multiplexing and demultiplexing
describes
ISA_CLK2X
ISA_CLK
DMA_ENC[0]
DMA_ENC[1]
DMA_ENC[2]
a
Release 1.5 - January 29, 2002
complete
DRQ[0]
DRQ[1]
DRQ[2]
DRQ[3]
DRQ[4]
DRQ[5]
DRQ[6]
DRQ[7]
logic can be simplified when only few DMA
channels are used in the application.
This glue logic is not needed in Local bus mode as
it does not support DMA transfers.
1C0
1C1
1C2
1C3
2C0
2C1
2C2
2C3
A
B
A
B
C
G1
G2A
74x153
74x138
1G
G2B
2G
Y0#
Y1#
Y2#
Y3#
Y4#
Y5#
Y6#
Y7#
1Y
2Y
DACK0#
DACK1#
DACK2#
DACK3#
DACK5#
DACK6#
DACK7#
DREQ_MUX[0]
DREQ_MUX[1]