Kontron EPIC/CE, User Manual

Page: 51 / 101

17 General Purpose Inputs/outputs
Kontron User's Guide EPIC/CE 51
Selecting a Logical Device
You can select a logical device by writing the value 07hex to the Index Register address and the logical
device number to the Data Register address. The example below shows how to select logical device 7 of
the first Super-I/O controller.
Example code:
MOV DX,2EH ;Index Register Address
MOV AL,07H ;Logical Device Select Code
OUT DX,AL ;
MOV DX,2FH ;Data Register Address
MOV AL,07H ;Logical Device Number
OUT DX,AL ;
Reprogramming Configuration Registers of the Logical Device
After a logical device is selected, a set of configuration registers is available. These registers are
responsible for the configuration of the GPIO functionality. You can set the direction (input/output) of
every single GPIO with the configuration register F0hex. You also can invert every single GPIO for read as
well as write operation by setting the corresponding bit in the configuration register F2hex.
Configuration register F1hex is the data register to read from or write to.
Configuration Register Purpose Explanation Default Value
F0hex Direction
0 = output,
1 = input
11111111bin
F1hex Data
Can only be read when programmed as
input, can be read/written when
programmed as output
00000000bin
F2hex Inversion
0 = not inverted,
1 = inverted
00000000bin
The meaning of the single bits in each of these configuration registers is shown in the table below.
Super-I/O
(Device)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
2
nd
(7) GP0 GP1 GP2 GP3 GP4 GP5 GP6 GP7
2
nd
(9) RSVD (*) RSVD (*) GP8 GP9 GP10 GP11 GP12 GP13
2
nd
(8) GP14 GP15 GP16 GP17 GP18 GP19 GP20 GP21
1
st
(7) RSVD (*) GP22 GP23 GP24 GP25 RSVD (*) RSVD (*) RSVD (*)
Notes : (*) Do not write to bits marked as reserved (RSVD).
These bits are used for other purposes. Normal operation of the board cannot be guaranteed if they
are intentionally modified!
The example below shows how a selected GPIO port (logical device) of the first Super-I/O can be read.
Example code:
MOV DX,2EH ;Index Register Address
MOV AL,F1H ;Select config register for data
OUT DX,AL ;
MOV DX,2FH ;Data Register Address
IN AL,DX ;Read data from data register