Register Map
13-14
Note:
Writing the DATA register when EP_Dir = 0 and reading from DATA register
when EP_Dir = 1 are denied.
13.2.4 Control Register (CTRL)
This set-only control register (CTRL) controls the FIFO and status of the
selected endpoint. A read access to this register always returns 0.
Note:
The endpoint 0 setup FIFO is always enabled and ready to accept setup
data. No control register (CTRL) is implemented for this FIFO, because the
local host cannot control it.
Table 13–5. Control Register (CTRL)
Bit
Name
Description
15–8
–
Reserved
7
Clr_Halt
Clear halt endpoint (non-isochronous)
6
Set_Halt
Set halt endpoint (non-isochronous)
5–3
–
Reserved
2
Set_FIFO_En
Set FIFO enable (non-isochronous)
1
Clr_EP
Clear endpoint
0
Reset_EP
Endpoint reset (non-Ctrl)
13.2.4.1
Clear Halt Endpoint (Clr_Halt)
Only concerns non-isochronous endpoints.
Used by the local host to clear an endpoint halt condition.
0:
No action
1: Clear halt condition
Always read 0.
Note:
It is not required to set the EP_Sel bit before setting this bit. Except when this
bit is set during the handling of an interrupt to the endpoint, the local host
must not set the EP_Sel bit before setting the Clr_Halt bit, in order to avoid
possible impacts on interrupts.