3. usb bits and pieces – Oki JOB60851 User Manual

Page 52

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Chapter 4 Software Development

page 4-17

4-3. USB Bits and Pieces

4-3-1.

Device Controller Specifications

Table 4.3.1 summarizes the ML60851C specifications. For detailed device specifications, see the
data sheet (Ml60851c.pdf).

Table 4.3.1. ML60851C Specifications

Data transfer speed

Full speed (12 Mb/s) only
Data flow type

Endpoint

Direction

Buffer size

In

8bytes

Control

EP0

Out

8bytes

EP1

In and out

64 bytes

×

2

Bulk

EP2

In and out

64bytes

Interrupt

EP3

In

8bytes

Endpoint

specifications

Isochronous

-

-

-

DMA

8/16-bit DMA request function (Endpoint 1: DMA request and acknowledge)

Power supply

Vcc3=3.0 to3.6V, Vcc5=3.0 to 5.5V
Interface to 5-volt microcontroller with local power supply (Vcc5)

Package

44-pin QFP or TQFP

4-3-2.

Overview of ML60851C Operation

Figure 4.3.1 is a block diagram for ML60851C internals. The basic structure and operation are both
simple. The receiver digitizes the inputs from the USB differential (D+/D-) data bus for the protocol
engine. The phase-locked loop (DPLL) synchronizes the protocol engine with the bus clock.

The protocol engine executes the transactions. It analyzes the time-multiplexed packets over the
USB bus looking for transactions including its assigned address. If it finds one, it analyzes the
request from the host to the corresponding endpoint and then accesses the appropriate buffer for
receiving from or transmitting to the USB bus.

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