LPC47M172_07 Datasheet, PDF (137/226 Pages) SMSC Corporation – Advanced I/O Controller with Motherboard GLUE Logic

Advanced I/O Controller with Motherboard GLUE Logic
Datasheet
Note:
If any of the Alternate Function Select bits in GP20 to GP23 registers are set for DDC function, the DDC
functions will be selected on all four GP20 to GP23 pins. However, it is recommended that the DDC
functions be selected via the Alternate Function Select bits in all of the GP20 to GP23 registers when
using the DDC functions.
The GP20 to GP23 registers are defined in Chapter 8 Power Control Runtime Registers and Chapter 10
Runtime Register Block Runtime Registers.
DDC VS. GPIO
ALTERNATE
FUNCTION SELECT
BIT/S
GPIO/EETI/Reserved
DDC (DEFAULT)
DDC (DEFAULT)
Table 7.32 - VGA DDCSDA Voltage Translation Logic
DDCSDA_3V
Don’t Care
0V
3.6V (max)
DDCSDA_5V
Don’t Care
0V
5.5V (max)
CURRENT ACROSS THE SWITCH
No Current flow (0 mA)
Current flows from DDCSDA_5V or
DDCSDA_3V
No Current flow (0 mA)
DDC Vs. GPIO
ALTERNATE
FUNCTION SELECT
BIT/S
GPIO/EETI/Reserved
DDC (DEFAULT)
DDC (DEFAULT)
Table 7.33 - VGA DDCSCL Voltage Translation Logic
DDCSCL_3V
Don’t Care
0V
3.6V (max)
DDCSCL_5V
Don’t Care
0V
5.5V (max)
CURRENT ACROSS THE SWITCH
No Current flow (0 mA)
Current flows from DDCSCL_5V or
DDCSCL_3V
No Current flow (0 mA)
SMSC LPC47M172
Page 137
DATASHEET
SMSC/Non-SMSC Register Sets (Rev. 01-11-07)