Silicon Laboratories C8051F344 Manuel D’Utilisation

Endpoints1-3 OUT are managed via USB registers EOUTCSRL and EOUTCSRH. All OUT endpoints can 
be used for Interrupt, Bulk, or Isochronous transfers. Isochronous (ISO) mode is enabled by writing ‘1’ to 
the ISO bit in register EOUTCSRH. Bulk and Interrupt transfers are handled identically by hardware.

An Endpoint1-3 OUT interrupt may be generated by the following:

1.

Hardware sets the OPRDY bit (EINCSRL.0) to ‘1’.

2.

Hardware generates a STALL condition.

When the ISO bit (EOUTCSRH.6) = ‘0’ the target endpoint operates in Bulk or Interrupt mode. Once an 
endpoint has been configured to operate in Bulk/Interrupt OUT mode (typically following an Endpoint0 
SET_INTERFACE command), hardware will set the OPRDY bit (EOUTCSRL.0) to ‘1’ and generate an 
interrupt upon reception of an OUT token and data packet. The number of bytes in the current OUT data 
packet (the packet ready to be unloaded from the FIFO) is given in the EOUTCNTH and EOUTCNTL reg-
isters. In response to this interrupt, firmware should unload the data packet from the OUT FIFO and reset 
the OPRDY bit to ‘0’. 

Bit7:

DBIEN: IN Endpoint Double-buffer Enable.
0: Double-buffering disabled for the selected IN endpoint.
1: Double-buffering enabled for the selected IN endpoint.

Bit6:

ISO: Isochronous Transfer Enable.
This bit enables/disables isochronous transfers on the current endpoint.
0: Endpoint configured for bulk/interrupt transfers.
1: Endpoint configured for isochronous transfers.

Bit5:

DIRSEL: Endpoint Direction Select.
This bit is valid only when the selected FIFO is not split (SPLIT = ‘0’).
0: Endpoint direction selected as OUT.
1: Endpoint direction selected as IN.

Bit4:

Unused. Read = ‘0’. Write = don’t care.

Bit3:

FCDT: Force Data Toggle.
0: Endpoint data toggle switches only when an ACK is received following a data packet 
transmission.
1: Endpoint data toggle forced to switch after every data packet is transmitted, regardless of 
ACK reception.

Bit2: 

SPLIT: FIFO Split Enable.
When SPLIT = ‘1’, the selected endpoint FIFO is split. The upper half of the selected FIFO is 
used by the IN endpoint; the lower half of the selected FIFO is used by the OUT endpoint.

Bits1–0: Unused. Read = 00b; Write = don’t care.

R/W

R/W

R/W

R

R/W

R/W

R

R

Reset Value

DBIEN

ISO

DIRSEL

-

FCDT

SPLIT

-

-

00000000

Bit7

Bit6

Bit5

Bit4

Bit3

Bit2

Bit1

Bit0

USB Address:

0x12