Datasheet

 1999-2013 Microchip Technology Inc. Preliminary DS41124D-page 65

PIC16C745/765

10.5.1.6 USB Control Register (UCTRL)

The control register provides various control and con-

figuration information for the USB.

U-0 U-0 R-X R/C-0 R/W-0 R/W-0 R/W-0 U-0

— —

SE0 PKT_DIS DEV_ATT RESUME SUSPND

— R = Readable bit

W = Writable bit

C = Clearable bit

U = Unimplemented bit,

read as ‘0’

-n = Value at POR reset

X = Don’t care

bit7 bit0

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: DEV_ATT: Device Attach

Enables the 3.3V output.

1 = When DEV_ATT is set, the V

USB pin will be driven with 3.3V (nominal)

0 = The V

USB pins (D+ and D-) will be in a high impedance state

bit 2: RESUME: Setting this bit will allow the USB to execute resume signaling. This will allow the USB to

perform remote wake-up. Software must set RESUME to 1 for 10 mS then clear it to 0 to enable remote

wake-up. For more information on RESUME signaling, see Section 7.1.7.5, 11.9 and 11.4.4 in the USB 1.1

specification.

1 = Perform RESUME signaling

0 = Normal operation

bit 1: SUSPND: Suspends USB operation and clocks and places the module in low power mode. This bit will

generally be set in response to a UIDLE interrupt. It will generally be reset after an ACTIVITY interrupt.

USB regulation will be different between suspend and non-suspend modes. 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

bit 0: Unimplemented: Read as ’0’