Information

USBx_OTGCTL field descriptions (continued)
Field Description
0 D- pulldown resistor is not enabled.
1 D- pulldown resistor is enabled.
3
Reserved
This read-only field is reserved and always has the value zero.
2
OTGEN
On-The-Go pullup/pulldown resistor enable
0 If USB_EN is set and HOST_MODE is clear in the Control Register (CTL), then the D+ Data Line pull-
up resistors are enabled. If HOST_MODE is set the D+ and D- Data Line pull-down resistors are
engaged.
1 The pull-up and pull-down controls in this register are used.
1–0
Reserved
This read-only field is reserved and always has the value zero.
40.4.9 Interrupt Status Register (USBx_ISTAT)
The Interrupt Status Register contains bits for each of the interrupt sources within the
USB Module. Each of these bits are qualified with their respective interrupt enable bits.
All bits of this register are logically OR'd together along with the OTG Interrupt Status
Register (OTGSTAT) to form a single interrupt source for the processor's interrupt
controller. After an interrupt bit has been set it may only be cleared by writing a one to
the respective interrupt bit. This register contains the value of 0x00 after a reset.
Addresses: USB0_ISTAT is 4007_2000h base + 80h offset = 4007_2080h
Bit 7 6 5 4 3 2 1 0
Read STALL ATTACH RESUME SLEEP TOKDNE SOFTOK ERROR USBRST
Write w1c w1c w1c w1c w1c w1c w1c w1c
Reset
0 0 0 0 0 0 0 0
USBx_ISTAT field descriptions
Field Description
7
STALL
Stall Interrupt
In Target mode this bit is asserted when a STALL handshake is sent by the SIE.
In Host mode this bit is set when the USB Module detects a STALL acknowledge during the handshake
phase of a USB transaction. This interrupt can be use to determine is the last USB transaction was
completed successfully or if it stalled.
6
ATTACH
Attach Interrupt
This bit is set when the USB Module detects an attach of a USB device. This signal is only valid if
HOSTMODEEN is true. This interrupt signifies that a peripheral is now present and must be configured.
5
RESUME
This bit is set depending upon the DP/DM signals, and can be used to signal remote wake-up signaling on
the USB bus. When not in suspend mode this interrupt should be disabled.
Table continues on the next page...
Chapter 40 Universal Serial Bus OTG Controller (USBOTG)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 901