UM10503
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User manual
Rev. 1.3 — 6 July 2012
622 of 1269
NXP Semiconductors
UM10503
Chapter 24: LPC43xx USB1 Host/Device controller
24.6.19 USB Endpoint Flush register (ENDPTFLUSH)
Writing a one to a bit(s) in this register will cause the associated endpoint(s) to clear any
primed buffers. If a packet is in progress for one of the associated endpoints, then that
transfer will continue until completion. Hardware will clear this register after the endpoint
flush operation is successful.
Table 487. USB Endpoint Prime register (ENDPTPRIME - address 0x4000 71B0) bit description
Bit
Symbol
Description
Reset
value
Access
3:0
PERB
Prime endpoint receive buffer for physical OUT endpoints.
For each OUT endpoint, a corresponding bit is set to 1 by software to request a
buffer be prepared for a receive operation for when a USB host initiates a USB
OUT transaction. Software should write a one to the corresponding bit
whenever posting a new transfer descriptor to an endpoint. Hardware will
automatically use this bit to begin parsing for a new transfer descriptor from the
queue head and prepare a receive buffer. Hardware will clear this bit when the
associated endpoint(s) is (are) successfully primed.
PERB0 = endpoint 0
...
PERB3 = endpoint 3
0
R/WS
15:4
-
Reserved
-
-
19:16
PETB
Prime endpoint transmit buffer for physical IN endpoints.
For each IN endpoint a corresponding bit is set to one by software to request a
buffer be prepared for a transmit operation in order to respond to a USB
IN/INTERRUPT transaction. Software should write a one to the corresponding
bit when posting a new transfer descriptor to an endpoint. Hardware will
automatically use this bit to begin parsing for a new transfer descriptor from the
queue head and prepare a transmit buffer. Hardware will clear this bit when the
associated endpoint(s) is (are) successfully primed.
PETB0 = endpoint 0
...
PETB3 = endpoint 3
0
R/WS
31:20
-
Reserved
-
-
Table 488. USB Endpoint Flush register (ENDPTFLUSH - address 0x4000 71B4) bit description
Bit
Symbol
Description
Reset
value
Access
3:0
FERB
Flush endpoint receive buffer for physical OUT endpoints.
Writing a one to a bit(s) will clear any primed buffers.
FERB0 = endpoint 0
...
FERB3 = endpoint 3
0
R/WC