Ampro Corporation 420 - Manual (Page 28)

Chapter 3 Hardware
22 Reference Manual CoreModule 420
PC/104 Bus Interface (P1A,B,C,D)
The PC/104 Bus uses a 104-pin 0.1" connector interface. This interface connector will carry all of the
appropriate PC/104 signals operating at clock speeds to 8.25 MHz. This interface connector is located
on both the top and bottom of the module.
Table 3-5. PC/104 Bus Interface Pin/Signal Descriptions (P1A)
Pin # Signal Description (P1 Row A)
1 (A1) IOCHCHK* 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.
2 (A2) SD7 System Data 7 – This signal (0 to 19) provides a system data bit.
3 (A3) SD6 System Data 6 – Refer to SD7, pin A2, for more information.
4 (A4) SD5 System Data 5 – Refer to SD7, pin A2, for more information.
5 (A5) SD4 System Data 4 – Refer to SD7, pin A2, for more information.
6 (A6) SD3 System Data 3 – Refer to SD7, pin A2, for more information.
7 (A7) SD2 System Data 2 – Refer to SD7, pin A2, for more information.
8 (A8) SD1 System Data 1 – Refer to SD7, pin A2, for more information.
9 (A9) SD0 System Data 0 – Refer to SD7, pin A2, for more information.
10 (A10) 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.
11 (A11) AEN Address Enable – This signal is reserved for the ISA Bus and is asserted
during DMA cycles to prevent I/O slaves from misinterpreting DMA
cycles as valid I/O cycles.
12 (A12) SA19 System Address 19 – These signals (0 to 19) provide system address bits.
13 (A13) SA18 System Address 18 – Refer to SA19, pin A12, for more information.
14 (A14) SA17 System Address 17 – Refer to SA19, pin A12, for more information.
15 (A15) SA16 System Address 16 – Refer to SA19, pin A12, for more information.
16 (A16) SA15 System Address 15 – Refer to SA19, pin A12, for more information.
17 (A17) SA14 System Address 14 – Refer to SA19, pin A12, for more information.
18 (A18) SA13 System Address 13 – Refer to SA19, pin A12, for more information.
19 (A19) SA12 System Address 12– Refer to SA19, pin A12, for more information.
20 (A20) SA11 System Address 11 – Refer to SA19, pin A12, for more information.
21 (A21) SA10 System Address 10 – Refer to SA19, pin A12, for more information.
22 (A22) SA9 System Address 9 – Refer to SA19, pin A12, for more information.
23 (A23) SA8 System Address 8 – Refer to SA19, pin A12, for more information.
24 (A24) SA7 System Address 7 – Refer to SA19, pin A12, for more information.
25 (A25) SA6 System Address 6 – Refer to SA19, pin A12, for more information.
26 (A26) SA5 System Address 5 – Refer to SA19, pin A12, for more information.