Datasheet

Miscellaneous and GPIO Configuration Registers
9−7
SLLS535E − April 2008 TUSB6250
9.7 PUPDSLCT_ATPOUT: Pullup and Pulldown Resistor Selection Register for
ATA/ATAPI Outputs (XDATA at F08F)
The PUPDSLCT_ATPOUT register allows the MCU to select the desired integrated pullup or pulldown
resistors for the TUSB6250 ATA/ATAPI output terminals. Normally, these resistors are not used in functional
operation. However, they can be used to help achieve the low-power suspend budget for bus-powered
applications. All pulldown resistors on the ATA/ATAPI bus are enabled as a power-up default, because the
TUSB6250 ATA/ATAPI output buffers are turned off during power up. The MCU must write to the
PUPDPWDN_ATPOUT register to disable all the undesired pulldown resistors when it is ready to enable and
drive the ATA/ATAPI bus.
Each bit in the PUPDSLCT_ATPOUT register can be configured individually by the MCU by:
• If the MCU sets any bit to 1, the pullup resistor is enabled and the pulldown resistor is disabled.
• If the MCU clears any bit to 0, the pulldown resistor is enabled and the pullup resistor is disablted.
The power-up default is the pulldown resistor enabled and the pullup resistor disabled for all the ATA/ATAPI
output pins.
76543210
RSV PUSLRSTATA PUSLDIOW PUSLDIOR PUSLDMACK PUSLDA PUSLCS1 PUSLCS0
R/O R/W R/W R/W R/W R/W R/W R/W
BIT NAME RESET FUNCTION
0 PUSLCS0 0 CS0 pin pullup/pulldown resistor selection by the MCU.
1 PUSLCS1 0 CS1 pin pullup/pulldown resistor selection by the MCU.
2 PUSLDA 0 DA2, DA1, and DA0 pins pullup/pulldown resistor selection by the MCU.
3 PUSLDMACK 0 DMACK pin pullup/pulldown resistor selection by the MCU.
4 PUSLDIOR 0 DIOR pin pullup/pulldown resistor selection by the MCU.
5 PUSLDIOW 0 DIOW pin pullup/pulldown resistor selection by the MCU.
6 PUSLRSTATA 0 RST_ATA pin pullup/pulldown resistor selection by the MCU.
Whenever the MCU sets the HARD_RST bit in the ATPIFCNFG1 register, this bit is cleared,
which means the pulldown resistor is selected.
7 RSV 0 Reserved = 0