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Section 26 USB 2.0 Host/Function Module
Page 1472 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
26.4 Operation
26.4.1 System Control and Oscillation Control
This section describes the register operations that are necessary to the initial settings of this
module, and the registers necessary for power consumption control.
(1) Resets
Table 26.15 lists the types of controller resets. For the initialized states of the registers following
the reset operations, see section 26.3, Register Description.
Table 26.15 Types of Reset
Name Operation
Power-on reset Low level input from the RES pin
USB bus reset Automatically detected by this module from the D and D lines when the
function controller function is selected
(2) Controller Function Selection
This module can select the host controller function or function controller function using the
DCFM bit in SYSCFG. Changing the DCFM bit should be done in the initial settings immediately
after a power-on reset or in the D+ pull-up disabled (DPRPU = 0) and D + /D pull-down
disabled (DRPD = 0) state.
(3) Enabling High-Speed Operation
This module can select a USB communication speed (communication bit rate). When the host
controller function is selected, the high-speed operation or full-speed/low-speed operation can be
set. When the function controller function is selected, either the high-speed operation or full-speed
operation can be selected. In order to enable the high-speed operation for this module, the HSE bit
in SYSCFG should be set to 1. If high-speed mode has been enabled, this module executes the
reset handshake protocol, and the USB communication speed is set automatically. The results of
the reset handshake can be confirmed using the RHST bit in DVSTCTR.
If high-speed operation has been disabled, this module operates at full-speed or low-speed. If the
function controller function is also selected, this module operates at full-speed.
Changing the HSE bit should be done between the ATTCH interrupt detection and bus reset
execution when the host controller function is selected, or with the D+ line pull-up disabled
(DPRPU = 0) when the host controller function is selected.