Specifications

PC/II+p Board Technical Reference Manual 27

5.5 PC/104 Bus Drive Current

The PC/104 bus drive current is specified by the PC/104 Specification, Version 1.3, listed in section 2.2. The

PC/II+p board complies to this standard. Most PC/104 bus signals have a reduced bus drive requirement of 4

mA. The 4 exceptions are open collector driven signals, which must drive 330-ohm pullup resistors defined

by the P996 specification.

The following signals must be driven with devices capable of providing 20 mA sink current:

MEMCS16#, IOCS16#, MASTER# and ENDXFR#.

All other signals may be driven with devices capable of providing 4 mA sink current. The following table of

source and sink currents apply to devices attached to the PC/104 (ISA) bus connector for the PC/II+p:

Table 7 Electrical – PC/104 Bus Drive Current

Symbol Sink Source Units

IRQ[15:14], IRQ[11:9], IRQ[7:3] 9.6 9.6 mA

RESETDRV 12 16 mA

SD[15:8] 12 12 mA

SD[7:0] 12 12 mA

SA[19:17] 12 12 mA

SA[16:0] 12 12 mA

SBHE# 12 12 mA

LA[23:17] 12 12 mA

IOCS16# -` -

MEMCS16# 12 20 mA

MEMR# 12 12 mA

MEMW# 12 12 mA

AEN 12 12 mA

IOCHRDY 12 20 mA

ENDXFR# (NOWS#) - -

IOCHCHK# - -

SYSCLK 12 12 mA

BALE 12 12 mA

IOR# 12 16 mA

IOW# 12 12 mA

SMEMR# 12 12 mA

SMEMW# 12 12 mA

DRQ[7:5], DRQ[3:0]`2`3`1`5`6`7 Schmitt Schmitt

DACK[7:5]#, DACK[3:0]# 9.6 9.6 mA

TC - -

REFRESH# - - mA

MASTER# - -

Over Recommended Operating Conditions