Chapter 3 Hardware
CoreModule 420 Reference Manual 25
Pin # Signal Description (P1 Row C)
6 (C5) LA20 Lactchable Address 20 – Refer to LA23, pin C2, for more information.
7 (C6) LA19 Lactchable Address 19 – Refer to LA23, pin C2, for more information.
8 (C7) LA18 Lactchable Address 18 – Refer to LA23, pin C2, for more information.
9 (C8) LA17 Lactchable Address 17 – Refer to LA23, pin C2, for more information.
10 (C9) MemR* Memory Read – This signal instructs a selected memory device to drive
data onto the data bus. It is active on all memory read cycles.
11 (C10) MemW* Memory Write – This signal instructs a selected memory device to store
data currently on the data bus. It is active on all memory write cycles.
12 (C11) SD8 System Data 8 – Refer to SD7, pin A2, for more information.
13 (C12) SD9 System Data 9 – Refer to SD7, pin A2, for more information.
14 (C13) SD10 System Data 10 – Refer to SD7, pin A2, for more information.
15 (C14) SD11 System Data 11 – Refer to SD7, pin A2, for more information.
16 (C15) SD12 System Data 12 – Refer to SD7, pin A2, for more information.
17 (C16) SD13 System Data 13 – Refer to SD7, pin A2, for more information.
18 (C17) SD14 System Data 14 – Refer to SD7, pin A2, for more information.
19 (C18) SD15 System Data 15 – Refer to SD7, pin A2, for more information.
20 (C19) Key (NC) Key Pin (Not Connected)
Notes: The shaded area denotes power or ground. The signals marked with * indicate active low.
Table 3-8. PC/104 Bus Interface Pin/Signal Descriptions (P1D)
Pin # Signal Description (P1 Row D)
21 (D0) GND Ground
22 (D1) MCS16*
Memory Chip Select 16 – This is signal is driven low by a memory slave
device to indicates it is cable of performing a 16-bit memory data
transfer. This signal is driven from a decode of the LA23 to LA17
address lines.
23 (D2) IOCS16*
I/O Chip Select 16 – This signal is driven low by an I/O slave device to
indicate it is capable of performing a 16-bit I/O data transfer. This
signal is driven from a decode of the SA15 to SA0 address lines.
24 (D3) IRQ10
Interrupt Request 10 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
25 (D4) IRQ11
Interrupt Request 11 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
26 (D5) IRQ12 Interrupt Request 12 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
27 (D6) IRQ15 Interrupt Request 15 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
28 (D7) IRQ14 Interrupt Request 14 – Asserted by a device when it has pending interrupt
request. Only one device may use the request line at a time.
29 (D8) DAck0* DMA Acknowledge 0 – Used by DMA controller to select the I/O
resource requesting the bus, or to request ownership of the bus as a bus
master device. Can also be used by the ISA bus master to gain control of
the bus from the DMA controller.
30 (D9) DRQ0 DMA Request 0 – Used by I/O resources to request DMA service. Must
be held high until associated DACK0 line is active.
To Next Page
Loading...