HD6417727BP160CV Datasheet, PDF (746/1098 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/ SH7700 Series

Section 22 USB Pin Multiplex Controller
D+ Pull-up Control
Control D+ pull-up by using USB1_pwr_en pin in the system when the connection—notification
(D+ pull-up) to USB host or hub is wished to be inhibited (i.e., during high-priority processing or
initialization processing).
The D+ pull-up control signal and USBF_VBUS pin input signal should be controlled by using the
USB1_pwr_en pin and the USB cable VBUS (AND circuit) as is shown in examples of figures
22.2 and 22.4
D+ pull-up is inhibited when the USB1_pwr_en pin is high in examples of figures 22.2 to 22.5.
(The initial setting of the USB1_pwr_en pin is High.)
Pull-up D+ after confirming that USBF_VBUS pin became high, when the pull-up control is
performed directly by USB1_pwr_en pin as is shown in examples of figures 22.3 and 22.5.
D+ pull-up is inhibited when the USB1_pwr_en pin is low in examples of figures 22.3 and 22.5.
Use an IC such that allows voltage application when system power is off (for example,
HD74LV1G126A) for the pull-up control IC (IC2 in figures 22.2 to 22.5).
(The UDC core in the SH7727 holds the powered state when USBF_VBUS pin is low, regardless
of the D+/D− state.)
Detection of USB Cable Connection/Disconnection
As USB function controller in the SH7727 manages the state by hardware, USB_VBUS signal is
necessary to recognize connection or disconnection of the USB cable. The power supply signal
(VBUS) in the USB cable is used for USBF_VBUS. However, if the cable is connected to the
USB host or hub when the power of USB function controller (SH7727—installed system) is off, a
voltage of 5 V will be applied from the USB host or hub.
Therefore, use an IC such that allows voltage application when system power is off (for example,
HD74LV1G08A) for the IC1 in figures 22.2 to 22.5.
Rev.6.00 Mar. 27, 2009 Page 688 of 1036
REJ09B0254-0600