PIC16C745/765
10.5.1.6 USB Control Register (UCTRL)
The control register provides various control and con-
figuration information for the USB.
REGISTER 10-6: USB CONTROL REGISTER (UCTRL: 195h)
U-0
U-0
R-X
SE0
R/C-0
R/W-0
R/W-0
R/W-0
U-0
PKT_DIS Config_Bit RESUME SUSPND
—
—
—
R = Readable bit
W = Writable bit
bit7
bit0
C = Clearable bit
U = Unimplemented bit,
read as ‘0’
-n = Value at POR reset
X = Don’t care
bit 7-6: Unimplemented: Read as ’0’.
bit 5:
SE0: Live Single Ended Zero. This status bit indicates that the D+ and D- lines are both pulled to low.
1= single ended zero being received
0= single ended zero not being received
bit 4
PKT_DIS: The PKT_DIS bit informs the MCU that the SIE has disabled packet transmission and recep-
tion. Clearing this bit allows the SIE to continue token processing. This bit is set by the SIE when a Setup
Token is received allowing software to dequeue any pending packet transactions in the BDT before resum-
ing token processing. The PKT_DIS bit is set under certain conditions such as back to back SETUP
tokens. This bit is not set on every SETUP token and can be modified only when UCTRL.SUSPND = 0.
bit 3:
bit 2:
Config_Bit: Configuration bit used by firmware during enumeration.
RESUME: Setting this bit will allow the USB to execute resume signaling. This will allow the USB to per-
form remote wake-up. Software must set RESUMEto 1 for 10 mS then clear it to 0 to enable remote wake-
up. For more information on RESUMEsignaling, see Section 7.1.7.5, 11.9 and 11.4.4 in the USB 1.1 spec-
ification.
1= perform Resume signaling
0= normal operation
bit 1:
bit 0:
SUSPND: Suspends USB operation and clocks and places the module in low power mode. This bit will
generally be set in response to a UIDLEinterrupt. It will generally be reset after an ACTIVITY interrupt.
The VUSB pin will still be driven, however the transceiver outputs are disabled.
1= USB module in power conserve mode
0= USB module normal operation
Unimplemented: Read as ’0’.
1999 Microchip Technology Inc.
Advanced Information
DS41124A-page 65
MICROCHIP [ MICROCHIP ]
