EFM32WG Datasheet, PDF (305/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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The application must poll the USB_GRSTCTL register, until the TXFFLSH bit is cleared by the core,
which indicates the end of flush operation. To transmit new data on this endpoint, the application can
re-enable the endpoint at a later point.
15.4.4.2.3.5 Bulk IN Stall
These notes refer to Figure 15.25 (p. 305)
1. The application has scheduled an IN transfer on receiving the USB_DIEPx_INT.INTKNTXFEMP (IN
Token Received When TxFIFO Empty) interrupt.
2. When the transfer is in progress, the application must force a STALL on the endpoint. This could be
because the application has received a SetFeature.Endpoint Halt command. The application sets the
Stall bit, disables the endpoint and waits for the USB_DIEPx_INT.EPDISBLD (Endpoint Disabled)
interrupt. This generates STALL handshakes for the endpoint on the USB.
3. On receiving the interrupt, the application flushes the Non-periodic Transmit FIFO and clears the
USB_DCTL.SGNPINNAK (Global IN NP NAK) bit.
4. On receiving the ClearFeature.Endpoint Halt command, the application clears the Stall bit.
5. The endpoint behaves normally and the application can re-enable the endpoint for new transfers
Figure 15.25. Bulk IN Stall
H ost
USB
D e v ice
IN
NAK
INTKNTXFEMP
INTR
Applicat ion
idle( wait_int r)
XferSize = 1025 byt es
Pkt Cnt = 3
EPEna = 1
xac_t 1 of2
xac_t 2 of2
IN
512 bytes
ACK
IN
STALL
IN
STALL
new xact
IN
NAK
IN
512 bytes
xact_ 1 dat a rdy
set up_ np_in_ pkt
NPTXFEMP INT
set up_ np_in_ pkt
xact_ 2 dat a rdy
EPDisabled int r
set_ st all
ep_ disable;
1
do_in_ xfer
2
flush_ nper_ t x_ fifo;
3
Clr Global IN NP Nak
4
wait_for_ host/
app to clr stall
5
clr_ st all
INTIKNNTTRXFEMP
do_ in_ xfer
A CK
15.4.4.2.3.6 Incomplete Isochronous IN Data Transfers
This section describes what the application must do on an incomplete isochronous IN data transfer.
Internal Data Flow
1. An isochronous IN transfer is treated as incomplete in one of the following conditions.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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