USB333X datasheet(31/85 Pages) MICROCHIP

31 / 85 page

 2009 - 2015 Microchip Technology Inc.

DS00001880A-page 31

USB333x

Figure 5-8 below shows a timing diagram to illustrate the start-up of the USB333x. At T0, the supplies are stable and

the USB333x is held in reset mode. At T1, the Link drives RESETB high after the REFCLK has started. The RESETB

pin may be brought high asynchronously to REFCLK. Once, the 3.3V and 1.8V internal supplies become stable the

USB333x will apply the 15Kohm pull downs to the data bus and assert DIR until the internal PLL has locked. After the

PLL has locked, the USB333x will check that the Link has de-asserted STP and at T2 it will de-assert DIR and begin

ULPI operation.

The ULPI bus will be available as shown in Figure 5-8 in the time defined as TSTART given in Table 4-3. If the REFCLK

signal starts after the RESETB pin is brought high, then time T0 will begin when REFCLK starts. TSTART also assumes

that the Link has de-asserted STP. If the Link has held STP high the USB333x will hold DIR high until STP is de-

asserted. When the LINK de-asserts STP, it must be ready drive the ULPI data bus to idle (00h) for a minimum of one

clock cycle after DIR de-asserts.

5.6

USB On-The-Go (OTG)

The USB333x provides support for the USB OTG protocol. OTG allows the USB333x to be dynamically configured as

a host or peripheral depending on the type of cable inserted into the Micro-AB receptacle. When the Micro-A plug of a

cable is inserted into the Micro-AB receptacle, the USB device becomes the A-device. When a Micro-B plug is inserted,

the device becomes the B-device. The OTG A-device behaves similar to a Host while the B-device behaves similar to

a peripheral. The differences are covered in the “On-The-Go Supplement to the USB 2.0 Specification”. In applications

where only USB Host or USB Peripheral is required, the OTG Module is unused.

5.6.1

ID RESISTOR DETECTION

The ID pin of the USB connector is monitored by the ID pin of the USB333x to detect the attachment of different types

of USB devices and cables. For device only applications that do not use the ID signal the ID pin should be connected

to VDD33. The block diagram of the ID detection circuitry is shown in Figure 5-9 and the related parameters are given

in Table 4-9.

FIGURE 5-8:

ULPI START-UP TIMING

DIR

RESETB

STP

TSTART

REFCLK

SUPPLIES

STABLE

PHY Drives Idle

DATA[7:0]

REFCLK valid

PHY Tri-States

PHY Drives High

LINK Drives Low

RXCMD

IDLE

USB333X датащи(PDF) 31 Page - Microchip Technology

USB333X датащи(HTML) 31 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85

датащи скачать

ссылки URL