HS_USB2.0 host
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Doc ID 018672 Rev 1
22.6.10 USBINTR
register
The USBINTR is a RW register which enables to report corresponding interrupts to the
software. It means that when an enabling bit of this register is set and the corresponding
interrupt is active, an interrupt is generated and sent to the EHCI host controller, that issue
the interrupt request (IRQ26 for EHCI1). The USBINTR register bit assignments are given in
Note:
Interrupt sources that are disabled in this register (enabling bit set to 1‘b0) still appear in
USBSTS register allowing the software to poll for events.
[01]
USBERRINT
1‘h0
USB error interrupt.
This bit is set by the EHCI host controller when
completion of a USB transaction results in an error
condition (e.g., error counter underflow). If the TD on
which the error interrupt occurred also had its IOC bit
set, both this bit and USBINT bit are set.
[00]
USBINT
1‘h0
USB interrupt.
This bit is set by the EHCI host controller on the
completion of a USB transaction, which results in the
retirement of a TD that had its IOC bit set. The EHCI
host controller also sets this bit when a short packet
is detected (actual number of bytes received was less
than the expected number of bytes).
1. See EHCI documentation for the detailed definitions of the data structures TD, IOC, etc.
Table 355.
USBSTS register bit assignments (continued)
Bit
Name
Reset value Description
Table 356.
USBINTR register bit assignments
Bit
Name
Reset value Description
[31:06]
Reserved
-
Read: undefined. Write: should be zero.
[05]
Interrupt on Async
Advance Enable
1‘h0
When both this bit and the Interrupt on async
advance (IAA) bit in the USBSTS register are set, the
EHCI host controller will issue an interrupt at the next
interrupt threshold.
The interrupt is acknowledged by software clearing
the IAA bit.
[04]
Host System Error
Enable
1‘h0
When both this bit and the host system error (HSE)
bit in the USBSTS register are set, the EHCI host
controller will issue an interrupt.
The interrupt is acknowledged by software clearing
the HSE bit.
[03]
Frame List
Rollover Enable
1‘h0
When both this bit and the frame list rollover (FLR) bit
in the USBSTS register are set, the EHCI host
controller will issue an interrupt.
The interrupt is acknowledged by software clearing
the FLR bit.