Legacy-Free Keyboard/Embedded Controller with SPI and LPC Docking Interface
27.2.1.2 Exiting the Configuration State
The device exits the Configuration State when the following Config Key is successfully written to the
CONFIG PORT address.
Config Key = < 0xAA>
27.2.1.3 Read Accessing Configuration Port
The Configuration Port reads back a float condition when not in the Configuration State. The
Configuration Port reads back 0x00, after the Configuration Key 0x55 has been written to the
Configuration Port, but prior any further writes to the Configuration Port. After the Configuration Index
Register has been written to at least once (in the Configuration State), then the last value written to the
Configuration Index Register (via the Configuration Port) can be read back.
27.2.2 Configuration Sequence Example
To program the configuration registers, the following sequence must be followed:
Enter Configuration Mode
Configure the Configuration Registers
Exit Configuration Mode
The following is an example of a configuration program in Intel 8086 assembly language.
;----------------------------.
; ENTER CONFIGURATION MODE
|
;----------------------------'
MOV DX,02EH
MOV AX,055H
OUT DX,AL
;------------------------------------.
; CONFIGURE REGISTER CRE0,
; LOGICAL DEVICE 8
|
|
;------------------------------------'
MOV DX,02EH
MOV AL,07H
OUT DX,AL ;Point to LD# Config Reg
MOV DX,02FH
MOV AL, 08H
OUT DX,AL;Point to Logical Device 8
;
MOV DX,02EH
MOV AL,E0H
OUT DX,AL
MOV DX,02fH
MOV AL,02H
OUT DX,AL
; Point to CRE0
; Update CRE0
;-----------------------------.
; EXIT CONFIGURATION MODE
|
;-----------------------------'
MOV DX,02EH
MOV AX,0AAH
OUT DX,AL.
27.2.3 Base Address Configuration Registers
The LPC47N350 configuration ports base address is relocatable beyond the two addressing options
provided by the MODE pin. The ability to relocate the configuration ports base address can prevent
address conflicts. Registers CR26 and CR27 enable the relocatable configuration ports base address
function. CR26 is the configuration ports base address least significant byte; CR27 is the most
significant byte (Table 27.2). The configuration ports base address is relocatable on even-byte
boundaries; i.e., A0 = “0”. Valid configuration ports base address values are 0x0000 – 0x0FFE.
Prior to Vcc2 POR, the configuration ports base address are undefined. At Vcc2 POR, the configuration
ports base address is determined by the MODE pin.
Revision 1.1 (01-14-03)
278
SMSC LPC47N350
DATASHEET
SMSC [ SMSC CORPORATION ]
