M66290AFP datasheet(5/54 Pages) RENESAS

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USB DEVICE CONTROLLER

M66290AGP/FP

MITSUBISHI <DIGITAL ASSP>

USB DATA TRANSFER DESCRIPTIONS

M66290A is a USB dev ice controller correspond to all

the f our ty pes of transf er (control, bulk, isochronous,

and interrupt transf er), which is compatible to USB

specif ication 1.1.

M66290A acts USB f unctions as below automatically.

(1) Bit stuff ing/destuff ing

(2) CRC generate/check

(3) NRZI encode/decode

(4) Packet handling

(5) USB address check

(6) Bus error handling

Theref ore, when CPU transact the operations as

f ollows, USB transf er is realized.

(1) Response to the control transf er request

(2) Permission of store and transmission of the

transmit data into the endpoint buff er.

(Or read of the receiv ed data f rom the endpoint

buff er)

(3) Stall handling

(4) Suspend/resume handling

Below are the descriptions about the data transf er.

Data receive

In data receiv e, there are diff erences of its f unction

between setup transaction and out transaction.

In setup transaction, when receiv ed dev ice request

f rom host, 8By te request is alway s stored into f our

resistors.

When request data is receiv ed correctly ,sends back

ACK packet to host and at the same time, occurs

interrupt to CPU and urge CPU to read request.

In out transaction, af ter M66290A receiv ed OUT

token packet, host transmits data packet.

If packet of m aximum packet size or short packet

is stored into the endpoint FIFO of M66290A, and

moreov er, error is not occurred in that transf er,

M66290A transmits ACK packet to host and inf orms

CPU that the data was receiv ed by occurring buff er

ready interrupt.

If U SB protocol error is occurred in the host data

which receiv ed v ia USB bus, or if the endpoint FIFO

is f ull, M66290A does not transmit ACK packet to

host. Host knows that the error occurred because the

ACK packet does not come, and take a step such as

data resend.

Data transmit

When the data of endpoint FIFO, which corresponds to

transmit request by IN token packet, is ready , M66290A

transmit the corresponded data packet to USB bus.

If the ACK packet come f rom the host f or the transmitted

data packet, a transaction completed and the endpoint

FIFO becomes empty and urge CPU to write the next

transmit data by buff er ready interrupt.

If the transmit data, which correspond to transmit request

by IN token packet, is not exist in the endpoint FIFO,

M66290A transmit NAK packet to host when receiv ed

IN token packet f rom host and occurs interrupt and

request CPU to write transmit data.

When M66290A receiv ed IN token packet again f rom host,

M66290A transmits the data which is written.

If error is not occurred in that transf er, host transmit ACK

packet and if M66290A receiv ed it normally , a transaction

completed.

If U SB protocol error is occurred in the data which is

transmitted v ia USB bus, host does not transmit ACK

packet, so M66290A watch and wait until receiv e IN token

packet, with keeping the data to be transmitted.

M66290AFP Datasheet(PDF) 5 Page - Renesas Technology Corp

M66290AFP Datasheet(HTML) 5 Page - Renesas Technology Corp

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