Panasonic JB-3300 Technical Manual page 234

Option Slot Connector
The table below and on the following pages describes the signals to the
option slot connector.
Table 5-13 Option Slot Connector Signal Description (1/3)
Signal I/O Description
DBO-DB7
T/O Data lines 0-7: Active high, 8-bit bidirectional
data lines are used to transfer data among the
processor, I/O devices, and memory. DBO is the
least significant bit (LSB).
ABO-AB19
Address lines 0-19: Active high, address lines
are used to span 1 M byte memory or 64K bytes I/O
address space. ABO is the LSB, while AB19 is the
MSB. The address may be generated by the 8088
processor or the DMA controller.
IRQ2-IRQ7
Interrupt request lines 2-7: Signals on these
lines are input from I/O adapters to the inter-
rupt controller to indicate interrupt request to
the processor. IRQ2 has the highest priority,
while IRQ7 has the lowest. While the rising
leading edge of these signals causes an interrupt
request, they may be held high until an acknow-
ledge signal (*INTA) is returned from the
processor.
DREQ1-DREQ3
DMA reguest lines 1-3: Active-high, used to
request DMA services. DREQ1 has the highest
priority, while DREQ3 has the lowest. These
lines must be kept high until the DMA controller
issues the acknowledgement signal *DACK.
*DACKO-*DACK3
DMA acknowledge lines 0-3: The DMA controller
issues its acknowledgement through one of these
four active-low lines.
*DACKO is used to refresh system dynamic memory.
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