Instruction Manual
Chapter 3 Hardware
30 Reference Manual ETX-PVR
Note: The shaded areas denote power or ground. The * symbol indicates the signal is Active Low.
81 IOCHRDY I/O Channel Ready – This signal allows slower ISA boards to lengthen I/O or
memory cycles by inserting wait states. This signal’s normal state is active high
(ready). ISA boards drive the signal inactive low (not ready) to insert wait
states. Devices using this signal to insert wait states should drive it low
immediately after detecting a valid address decode and an active read, or write
command. The signal is released high when the device is ready to complete the
cycle.
82 NS Not Supported
83, 84
VCC DC Power – +5 volts +/- 5%
85 SD0 System Data 0 – Refer to SD14, pin-3 for more information.
86 SMEMW* System Memory Write – This signal is used by bus owner to request a memory
device to store data currently on the data bus and only active for the lower
1 MB. Used for legacy compatibility with 8-bit cards.
87 SD2 System Data 2 – Refer to SD14, pin-3 for more information.
88 SD1 System Data 1 – Refer to SD14, pin-3 for more information.
89 SD3 System Data 3 – Refer to SD14, pin-3 for more information.
90 NOWS* No Wait State – This signal is driven low by a bus slave device to indicate it is
capable of performing a bus cycle without inserting any additional wait states.
To perform a 16-bit memory cycle without wait states, this signal is derived
from an address decode.
91 NS Not Supported
92 SD4 System Data 4 – Refer to SD14, pin-3 for more information.
93 SD5 System Data 5 – Refer to SD14, pin-3 for more information.
94 IRQ9 Interrupt Request 9 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
95 SD6 System Data 6 – Refer to SD14, pin-3 for more information.
96 SD7 System Data 7 – Refer to SD14, pin-3 for more information.
97 IOCHK* I/O Channel Check – This signal may be activated by ISA boards to request that
a non-maskable interrupt (NMI) be generated to the system processor. It is
driven active to indicate an uncorrectable error has been detected.
98 RSTDRV Reset Drive – This signal is used to reset or initialize system logic on power up
or subsequent system reset.
99
GND Ground
100
GND Ground
Table 3-5. Complete X2 ISA Bus Interface Pin Signal Descriptions (J2) (Continued)