Chandru, >> What is the difference between pullup/pulldown selection and pullup >> enable bits in the pad configuration register of omap 3430 processor? [Brandon] : There are 2 bits to control pullup/pulldown scenario. The PULLTYPESELECT determines whether a pullup resistor is connected to the pad, or a pulldown resistor is connected to the pad. The PULLUDENABLE is used to then enable this functionality. You could use this to place input pins into a known state when logic outside the device is releasing that pin into a high-z state. >> what is the meaning of input enable or offmode bits and why it is needed. [Brandon] : The MUXMODE field should be straightforward. This is determining what functionality is actually connected to the pin, as many pins have several peripherals potentially brought out to it. The safe mode avoids any risk of electrical contention by configuring the pin as an input with no functional interface mapped to it. [Brandon] : The Off Mode configuration fields support the CORE power domain off state management. The OMAP3 device supports placing the CORE logic (peripherals, interconnect, etc) into a power off state, or retention state to minimize leakage currents. However, reactivity to wake-up events must still be ensured. The device supports an off-mode management scheme that allows deactivation of all modules, isolation of their outputs and configuration of a dedicated off mode on the I/O pads of the device. For each pin, the following bits are used during this OFF mode scenario. OFFENABLE : Off mode pin state override control Combined with output of PRCM OFF_MODE to switch I/O pad control From functional path to the rest of the bits below. OFFOUTENABLE : Off mode output enable. When enabled by PRCM.OFF_MODE AND OFFENABLE, this controls the Output buffer to be in high-Z (=1) or OFFOUTVALUE (=0). OFFOUTVALUE : Off mode output value OFFPULLUDENABLE : Off mode pullup/pulldown enable. Enabled when if OFF mode OFFPULLTYPESELECT : Off mode pullup/pulldown selection. Enabled when if OFF mode Brandon Azbell -----Original Message----- From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of chandru vijayashankar Sent: Sunday, June 15, 2008 8:47 AM To: linux-omap@xxxxxxxxxxxxxxx Subject: pad configuration register doubt Hi all, In the arch/arm/mach-omap2/mux.c file. i have some doubts of the structure omap34xx_pins. What is the difference between pullup/pulldown selection and pullup enable bits in the pad configuration register of omap 3430 processor. any help on the different bits in the control pad configuration register. why and where they are used. what is the meaning of input enable or offmode bits and why it is needed. With Warm Regards, chandru -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
