Register Map
13-36
13.2.13
Non-Isochronous Endpoint Interrupt Status Register (EPN_STAT)
The read-only non-isochronous endpoint interrupt status register
(ENP_STAT) identifies the non-isochronous endpoint causing an EPn inter-
rupt. A write into it is forbidden.
If a non-transparent transaction occurs before a previous one on another end-
point in the same direction has been handled by the local host, the second
interrupt is asserted only after first one has been cleared by the local host and
EPN_STAT is updated with the corresponding interrupt assertion.
Table 13–14. Non-Isochronous Endpoint Interrupt Status Register (EPN_STAT)
Bit
Name
Description
15–12
–
Reserved
11–8
EPn_RX_IT_src
Receive endpoint interrupt source (non-isochronous)
7–4
–
Reserved
3–0
EPn_TX_IT_src
Transmit endpoint interrupt source (non-isochronous)
13.2.13.1
Receive Endpoint Interrupt Source (EPn_RX_IT_src)
Only concerns non-isochronous endpoints. When the EPn_RX flag bit is set,
the endpoint causing the interrupt condition is encoded in these four register
bits. When the EPn_RX flag bit is cleared, the four bits read as 0.
0000: No receive endpoint interrupt is pending.
0001: EP1
…
.
1111: EP15
Value after local host or USB reset is low (all 4 bits).
13.2.13.2
Transmit Endpoint Interrupt Source (EPn_TX_IT_src)
Only concerns non-isochronous endpoints.
When the EPn_TX flag is set, the endpoint causing this flag to be set is en-
coded in these four register bits. When the EPn_TX flag is cleared, the four bits
read as 0.
0000: No transmit endpoint interrupt is pending.
0001: EP1
…
.
1111: EP15
Value after local host or USB reset is low (all 4 bits).