TME-CLR-ECO-R0V6.docx
Rev 0.6
Page 24 of 34
3.10
PC/104 Bus (X21)
The PC/104 bus is a modification of the industry standard (ISA) PC bus specified in IEEE P996. The PC/104 bus
has different mechanics than IEEE P966 to allow the stacking of modules.
The main features are:
•
Supports programmable extra wait state for ISA cycles
•
Supports I/O recovery time for back-to-back I/O cycles
The following table shows the pin assignment of the PC/104 connector.
Note:
-5V0 on the PC/104 connector is not supported on this board.
PC/104 Bus Connector
Pin
Row A
Row B
1
IOCHCK
GND
2
D7
RSTDRV
3
D6
+5V-ALWAYS
4
D5
IRQ9
5
D4
NC
6
D3
DRQ2
7
D2
-12V
Pin
Row D
Row C
8
D1
NC
0
GND
GND
9
D0
+12V
1
MEMCS16
SBHE
10
IOCHRDY
NC
2
IOCS16
LA23
11
AEN
SMEMW
3
IRQ
LA22
12
A19
SMEMR
4
IRQ
LA21
13
A18
IOW
5
IRQ
LA20
14
A17
IOR
6
IRQ
LA19
15
A16
DACK3
7
IRQ
LA18
16
A15
DRQ3
8
DACK
LA17
17
A14
DACK1
9
DRQ
MEMR
18
A13
DRQ1
10
DACK
MEMW
19
A12
REFRESH
11
DRQ
SD8
20
A11
SYSCLK
12
DACK
SD9
21
A10
IRQ7
13
DRQ
SD10
22
A9
IRQ6
14
DACK
SD11
23
A8
IRQ5
15
DRQ
SD12
24
A7
IRQ4
16
+5V-ALWAYS
SD13
25
A6
IRQ3
17
MASTER
SD14
26
A5
DACK2
18
GND
SD15
27
A4
TC
19
GND
GND
28
A3
BALE
29
A2
+5V-ALWAYS
30
A1
OSC
31
A0
GND
32
GND
GND
Note:
The vo5V-ALWAYS, +12V and -12V are not generated by the
onboard power-supply but they are routed from the Power Supply
Connector. The maximum current is limited depending on voltage:
+12V < 1A; -12V < 0.3 A; +5V-ALWAYS < 3 A
One pin can be used for 1A at maximum.