Information

USBx_INTEN field descriptions (continued)
Field Description
0 Disbles the SOFTOK interrupt.
1 Enables the SOFTOK interrupt.
1
ERROREN
ERROR Interrupt Enable
0 Disables the ERROR interrupt.
1 Enables the ERROR interrupt.
0
USBRSTEN
USBRST Interrupt Enable
0 Disables the USBRST interrupt.
1 Enables the USBRST interrupt.
42.5.11 Error Interrupt Status register (USBx_ERRSTAT)
Contains enable bits for each of the error sources within the USB Module. Each of these
bits are qualified with their respective error enable bits. All bits of this register are
logically OR'd together and the result placed in the ERROR bit of the ISTAT register.
After an interrupt bit has been set it may only be cleared by writing a one to the
respective interrupt bit. Each bit is set as soon as the error conditions is detected.
Therefore, the interrupt does not typically correspond with the end of a token being
processed. This register contains the value of 0x00 after a reset.
Address: 4007_2000h base + 88h offset = 4007_2088h
Bit 7 6 5 4 3 2 1 0
Read BTSERR 0 DMAERR BTOERR DFN8 CRC16 CRC5EOF PIDERR
Write w1c w1c w1c w1c w1c w1c w1c
Reset
0 0 0 0 0 0 0 0
USBx_ERRSTAT field descriptions
Field Description
7
BTSERR
This bit is set when a bit stuff error is detected. If set, the corresponding packet is rejected due to the error.
6
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
5
DMAERR
This bit is set if the USB Module has requested a DMA access to read a new BDT but has not been given
the bus before it needs to receive or transmit data. If processing a TX transfer this would cause a transmit
data underflow condition. If processing a RX transfer this would cause a receive data overflow condition.
This interrupt is useful when developing device arbitration hardware for the microprocessor and the USB
module to minimize bus request and bus grant latency. This bit is also set if a data packet to or from the
host is larger than the buffer size allocated in the BDT. In this case the data packet is truncated as it is put
in buffer memory.
4
BTOERR
This bit is set when a bus turnaround timeout error occurs. The USB module contains a bus turnaround
timer that keeps track of the amount of time elapsed between the token and data phases of a SETUP or
Table continues on the next page...
Chapter 42 Universal Serial Bus OTG Controller (USBOTG)
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
Freescale Semiconductor, Inc.
Preliminary
1049
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