Renesas H8S/2158, User Manual

Page: 635 / 929

Section 18 Universal Serial Bus Interface (USB)
Rev. 3.00 Jan 25, 2006 page 581 of 872
REJ09B0286-0300
18.3.11 USB Control /Status Register 0 (USBCSR0)
USBCSR0 controls the operation of the USB function core.
USBCSR0 is initialized to H'00 by a system reset or function software reset (see section 18.3.16,
USB Control Registers 0 and 1 (USBCR0, USBCR1)).
Bit Bit Name Initial Value R/W Description
7 to 4 — All 0 R Reserved
These bits are always read as 0 and cannot be modified.
3 EP0STOP 0 R/W Endpoint 0 Stop
Used to protect the contents of endpoint 0 FIFO in the
USB function core. Setting this bit to 1 protects the data
that is sent to the EP0 OUT-FIFO by a SETUP
transaction.
0: Indicates that the EP0 OUT-FIFO and specific FIFO is
in an operating state.
[Clearing conditions]
•
System reset
•
Function software reset
1: Indicates that the EP0 OUT-FIFO is in a read stop
state.
[Setting conditions]
•
FVSR0O contents are not changed by reading
EPDR0O.
Indicates that the EP0 specific FIFO is in a write or
transfer stop state.
•
FIFO contents are not changed by writing to EPDR0I.
•
FVSR0I contents are not changed by setting EP0ITE.