HP gx466 Manuale Utente

ECM-5510 User’s Manual 

 

47

 

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. 

OWS# 

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. 

 

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.