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Section 26 USB 2.0 Host/Function Module
R01UH0134EJ0400 Rev. 4.00 Page 1473 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
(4) USB Data Bus Resistor Control
Figure 26.1 shows a diagram of the connections between this module and the USB connectors.
This module incorporates a pull-up resistor for the D+ signal and a pull-down resistor for the D+
and D- signals. These signals can be pulled up or down using the DPRPU and DRPD bits in
SYSCFG.
When the function controller function is selected, set the DPRPU bit in the SYSCFG register to 1
and pull up the D+ signal after recognizing a connection to the USB host. When disconnection of
the USB host is recognized, manipulate the DPRPU and DCFM bits as follows:
(1) Clear the DPRPU bit to 0.
(2) Wait a minimum of 1 µs.
(3) Set the DCFM bit to 1.
(4) Wait a minimum of 200 ns.
(5) Clear the DCFM bit to 0.
This module controls the terminal resistor for the D+ and D- signals during high-speed operation
and the output resistor for the signals during full-speed operation. This module automatically
switches the resistor after connection with the host controller or peripheral device by means of
reset handshake, suspended state and resume detection.
When the function controller function is selected and the DPRPU bit in SYSCFG is cleared to 0
during communication with the host controller, the pull-up resistor (or the terminal resistor) of the
USB data line is disabled, making it possible to notify the USB host of the device disconnection.