Overview
13-7
USB Function Module
13.1.5.2
Hardware Detection
This detection can have two sources:
-
The GPIO(0) OMAP5910 input
-
The OMAP5910 input of the USB function I/O power supply (DVDD2)
The selection between these two sources is made by the
USB_W2FC_VBUS_MODE bit(17) of the MOD_CONF_CTRL_0 register (bit
usable only in OMAP5910 configuration mode):
-
USB_W2FC_VBUS_MODE = 0 (default): GPIO(0) is selected.
-
USB_W2FC_VBUS_MODE = : I/O power supply detection is selected.
GPIO0 Detection
This detection must be enabled by software as follows:
-
In either the OMAP1509 or OMAP5910 configuration mode, when the
VBUS_GPIO0_SELECT bit (12) (FUNC_MUX_CTRL_1 register) is set
Or
-
In the OMAP5910 configuration mode, when the CONF_GPIO0_MODE
bits (11:9) (FUNC_MUX_CTRL_7 register) are set to 010
The results of this detection are as follows:
-
GPIO0 input = 0: USB not connected (default value via internal pulldown)
-
GPIO0 input = 1: USB connected
I/O Power Supply Detection
An analog cell is used to detect the presence or not of the USB I/O power
supply (DVDD2), which permits the detection of the presence or absence of
the USB.
-
DVDD2 present: USB connected
-
DVDD2 not present: USB not connected