Renesas CPU Board M3A-HS19 Instrukcja Użytkownika Pobierz pdf (Strona 6)

SH7285/SH7286 USB Function Module

USB to Serial Conversion Application Note

2.4 Control Transfer

A control transfer is a USB transfer that uses the endpoint 0 default pipe and must be supported by all USB devices.

The USB host issues a USB standard request to the USB device and configures the device. A control transfer can be

used to issue a class- or vendor-specific request.

A control transfer is composed of a Setup stage, Data stage (not in all cases), and Status stage. The Data stage consists

of multiple bus transactions. Control transfers are supported via bi-directional communication flow, according to the

data direction of the Data stage. A control OUT transfer is the data flow from the USB host to the USB device during

the Data stage. A control IN transfer is the data flow from the USB device to the USB host during the Data stage. The

Data stage is completed when the USB host transmits an inverted token of the data direction. The Status stage is the

stage that transmits the inverted token to the USB host.

Figure 2.3 shows Data Direction During the Data Stage and

Figure 2.4 shows each Stage Configuration During Control Transfer.

Figure 2.3 Data Direction During the Data Stage

Figure 2.4 Stage Configuration During Control Transfer

REJ05B1152-0100/Rev.1.00 May 2008 Page 6 of 35

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Renesas CPU Board M3A-HS19 Instrukcja Użytkownika Strona 6