Instruction Manual

Chapter 3 Hardware
ETX-PVR Reference Manual 29
49 SA5 System Address 5 – Refer to SA0, pin-39 for more information.
50 IRQ4 Interrupt Request 4 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
51, 52
VCC DC Power – +5 volts +/- 5%
53 SA6 System Address 6 – Refer to SA0, pin-39 for more information.
54 IRQ5 Interrupt Request 5 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
55 SA7 System Address 7 – Refer to SA0, pin-39 for more information.
56 IRQ6 Interrupt Request 6 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
57 SA8 System Address 8 – Refer to SA0, pin-39 for more information.
58 IRQ7 Interrupt Request 7 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
59 SA9 System Address 9 – Refer to SA0, pin-39 for more information.
60 SYSCLK System Clock – This is a free running clock typically in the 8 MHz to 10 MHz
range, although its exact frequency is not guaranteed.
61 SA10 System Address 10 – Refer to SA0, pin-39 for more information.
62 REFSH* Memory Refresh – This signal is driven low to indicate a memory refresh cycle
is in progress. Memory is refreshed every 15.6 usec.
63 SA11 System Address 11 – Refer to SA0, pin-39 for more information.
64 NS Not Supported
65 SA12 System Address 12 – Refer to SA0, pin-39 for more information.
66 NS Not Supported
67, 68
GND Ground
69 SA13 System Address 13 – Refer to SA0, pin-39 for more information.
70 NS Not Supported
71 SA14 System Address 14 – Refer to SA0, pin-39 for more information.
72 NS Not Supported
73 SA15 System Address 15 – Refer to SA0, pin-39 for more information.
74 IOR* I/O Read – This strobe signal is driven by the owner of the bus (ISA bus master)
and instructs the selected I/O device to drive read data onto the data bus.
75 SA16 System Address 16 – Refer to SA0, pin-39 for more information.
76 IOW* I/O Write – This strobe signal is driven by the owner of the bus (ISA bus
master) and instructs the selected I/O device to capture the write data on the
data bus.
77 SA18 System Address 18 – Refer to SA0, pin-39 for more information.
78 SA17 System Address 17 – Refer to SA0, pin-39 for more information.
79 SA19 System Address 19 – Refer to SA0, pin-39 for more information.
80 SMEMR* System Memory Read – This signal is used by bus owner to request a memory
device to drive data onto the data bus and only active for lower 1 MB. Used for
legacy compatibility with 8-bit cards.
Table 3-5. Complete X2 ISA Bus Interface Pin Signal Descriptions (J2) (Continued)