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Section 20 USB Function Module
Rev. 4.00 Sep. 14, 2005 Page 786 of 982
REJ09B0023-0400
20.8
Example of USB External Circuitry
USB Transceiver: When an on-chip transceiver is not used, a USB transceiver IC (such as a
PDIUSBP11) must be connected externally. The USB transceiver manufacturer should be
consulted concerning the recommended circuit from the USB transceiver to the USB
connector, etc.
D+ Pull-Up Control: In a system where it is wished to delay USB host/hub connection
notification (D+ pull-up) (during high-priority processing or initialization processing, for
example), D+ pull-up is controlled using a general output port. When the USB cable has been
connected to the host or hub and D+ pull-up is inhibited, D+ and D- are placed in the low level
state (D+ and D- are pull down on the host or hub side) and the USB module recognizes as if the
USB bus reset has been received from the host. In that case, the D+ pull-up control signal and
VBUS pin input signal should be controlled using a general output port and the USB cable VBUS
(AND circuit) as shown in figure 20.17. (The UDC core of this LSI holds the powered state
independent of D+ and D- state when the VBUS pin is low level.)
Detection of USB Cable Connection/Disconnection: As USB states are managed by hardware in
this module, a VBUS signal that recognizes connection/disconnection is necessary. The power
supply signal (VBUS) in the USB cable is used for this purpose. However, if the cable is
connected to the USB host/hub when the on-chip function LSI power is off, a voltage (5 V) will be
applied from the USB host/hub. Therefore, an IC (HD74LV1G08A, 2G08A, etc.) that allows
voltage application when the system power is off should be connected externally.
Summary of Contents for HD6417641
Page 2: ...Rev 4 00 Sep 14 2005 Page ii of l...
Page 7: ...Rev 4 00 Sep 14 2005 Page vii of l...
Page 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
Page 12: ...Rev 4 00 Sep 14 2005 Page xii of l...
Page 28: ...Rev 4 00 Sep 14 2005 Page xxviii of l...
Page 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Page 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Page 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Page 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Page 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Page 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Page 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Page 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Page 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Page 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Page 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Page 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Page 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
Page 1032: ...Rev 4 00 Sep 14 2005 Page 982 of 982 REJ09B0023 0400 X X Y data addressing 52 X Y memory 193...
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