User’s Manual
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ROBO-503/ROBO-503N User’s Manual
3.7.16.4 Transfer Response
IOCS16#
This is an active low signal driven by an I/O-mapped PC-AT/PC104 adapter indicating that the
I/O device located at the address is a 16-bit device. This open collector signal is driven, based
on SA [15:0] only (not IOR# and IOW#) when AEN is not asserted.
MEMCS16#
This is an active low signal driven by a memory mapped PC-AT/PC104 adapter indicating that
the memory device located at the address is a 16-bit device. This open collector signal is
driven, based on LA [23:17] only.
0WS#
This signal is an active low open-collector signal asserted by a 16-bit memory mapped device
that may cause an early termination of the current transfer. It should be gated with MEMR# or
MEMW# and is not valid during DMA transfers. IOCHRDY precedes 0WS#.
IOCHRDY
This is an active high signal driven inactive by the target of either a memory or an I/O operation
to extend the current cycle. This open collector signal is driven based on the system address
and the appropriate control strobe. IOCHRDY precedes 0WS#.
IOCHCK#
This is an active low signal driven active by a PC-AT/PC104 adapter detecting a fatal error
during bus operation. When this open collector signal is driven low it will typically cause a non-
maskable interrupt.
3.7.16.5 Controls
SYSCLK
This clock signal may vary in frequency from 2.5 MHz to 25.0 MHz depending on the setup
made in the BIOS. Frequencies above 16 MHz are not recommended. The standard states 6
MHz to 8.33 MHz, but most new adapters are able to handle higher frequencies. The PC-
AT/PC104 bus timing is based on this clock signal.
OSC
This is a clock signal with a 14.31818 MHz ± 50 ppm frequency and a 50 ± 5% duty cycle. The
signal is driven by the permanent master.
RESETDRV
This active high signal indicates that the adapter should be brought to an initial reset condition.
This signal will be asserted by the permanent master on the bus for at least 100 ms at power-up
or watchdog time-out to ensure that adapters in the system are properly reset. When active, all
adapters should turn off or tri-state all drivers connected to the bus.
3.7.16.6 Interrupts
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.
