ML60852 Ver la hoja de datos (PDF) - Oki Electric Industry

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Fabricante

ML60852

USB Device Controller

Oki Electric Industry 

1Semiconductor

PEDL60852-01

ML60852

(4) Operation of control transfer

(a) Setup stage

The setup token and 8 bytes of setup data are transmitted from the host. The ML60852 decodes the setup token,

and automatically stores the 8 bytes of setup data in the setup register. When this is completed normally, the

ML60852 returns ACK to the host.

The 8-byte setup data is the standard request code defined in Section 9.3 of the USB Standards, or a code of the

requests unique to each device class, etc. The request is decoded on the local MCU side.

(b) Data stage

If the request specified by the 8-byte setup data is also accompanied by transfer of parameter data from the host

to the device, the transfer is a control write transfer, and the OUT token and the data packet are transmitted

from the host. When these are received normally, the ML60852 stores the parameter data in the EP0 receive

FIFO and returns ACK to the host.

If the request is accompanied by transfer of parameter data from the device to the host, the transfer is a control

read transfer, and when the host sends the IN token, the ML60852 sends the parameter data that was already

stored beforehand in the EP0 transmit FIFO by the local MCU. When the host receives this normally, it returns

an ACK to the ML60852.

On the other hand, in the case of requests that do not contain any parameter data that need to be transmitted or

received, this data stage will not be present and the processing proceeds directly to the status stage from the

setup stage.

(c) Status stage

The status stage is a stage intended for reporting the status of the result of executing a request from the device

to the host. During a control write transfer or a control transfer without data, the IN token is sent by the host,

and the ML60852 returns a response to it. During a control read transfer, the OUT token and data of zero

length are sent by the host, and the ML60852 returns a response to it.

During the above control transfers, the local MCU need only read from or write to the 8-byte setup registers

mapped at 00h to 07h, the EP0 transmit FIFO mapped at 70h, and the EP0 receive FIFO mapped at 78h

according to the interrupt cause, and all other operations will be carried out automatically by the ML60852.

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