HP AMD Geode ECM-5510 - Manual (Page 48)

ECM-5510
48 ECM-5510 User’s Manual
2.4.19.1.6 Interrupts
Signal Signal Description
IRQ[3:7], IRQ[9:12]
IRQ[14:15]
These signals are active high signals, which indicate the presence of an
interrupting PC-AT/PC104 bus adapter. Due to the use of pull-ups, unused
interrupt inputs must be masked.
2.4.19.1.7 Bus Arbitration
Signal Signal Description
DRQ[0:3], DRQ[5:7]
These signals are active high signals driven by a DMA bus adapter to indicate a
request for a DMA bus operation. DRQ [0:3] request 8 bit DMA operations, while
DRQ [5:7] request 16 bit operations. All bus DMA adapters will drive these lines
with a tri-state driver. The permanent master monitors these signals to determine
which of the DMA devices, if any, are requesting the bus.
DACK[0:3]#,
DACK[5:7]#
These signals are active low signals driven by the permanent master to indicate
that a DMA operation can begin. They are continuously driven by a totem pole
driver for DMA channels attached.
AEN
This signal is an active high totem pole signal driven by the permanent master to
indicate that the address lines are driven by the DMA controller. The assertion of
AEN disables response to I/O port addresses when I/O command strobes are
asserted. AEN being asserted, only the device with active DACKn# should
respond.
REFRESH#
This is an active low signal driven by the current master to indicate a memory
refresh operation. The current master will drive this line with a tri-state driver.
TC
This active high signal is asserted during a read or write command indicating that
the DMA controller has reached a terminal count for the current transfer. DACKn#
must be presented by the bus adapter to validate the TC signal.
MASTER# This signal is not supported by the chipset.