Philips Semiconductors

Product specification

PDIUSBD11

USB device with serial interface

1999 Jul 22

8

Clock Division Factor Byte

SV00828

76

5

4

3

2

1

1

1

0

POWER ON VALUE

CLOCK DIVISION FACTOR

RESERVED

10

XX

XX

Clock Division Factor

The value indicates clock division factor for

CLKOUT. The output frequency is

48 MHz/(N+1) where N is the Clock Division

Factor. The reset value is 11. This will

produce the output frequency of 4 MHz

which can then be programmed up (or down)

by the user. The minimum value is one giving

the range of frequency from 4 to 24 MHz.

The PDIUSBD11 design ensures no

glitching during frequency change. The

programmed value will not be changed by a

bus reset.

Data Flow Commands

Data flow commands are used to manage the data transmission

between the USB endpoints and the monitor. Much of the data flow

is initiated via an interrupt to the microcontroller. The microcontroller

utilizes these commands to access and determine whether the

endpoint FIFOs have valid data.

Read Interrupt Register

Command

: F4h

Data

: Read 2 bytes

Interrupt Register Byte 1

POWER ON VALUE

RESERVED

CONTROL OUT ENDPOINT

CONTROL IN ENDPOINT

ENDPOINT INDEX 4

ENDPOINT INDEX 5

ENDPOINT INDEX 6

ENDPOINT INDEX 7

76

5

4

3

2

X

1

X

0

00

00

00

SV00829

This command indicates the origin of an interrupt. A ‘1’ indicates an

interrupt occurred at this endpoint. The bits are cleared by reading

the endpoint status register through the Read Endpoint Status

command.

After a bus reset, an interrupt will be generated and bit 6 of the

Interrupt Register Byte 2 will be ‘1’. The interrupt is internally cleared

by reading the interrupt register. A bus reset is completely identical

to the hardware reset through the RESET_N pin with the sole

difference of interrupt notification.

Interrupt Register Byte 2

POWER ON VALUE

ENDPOINT INDEX 8

ENDPOINT INDEX 9

RESERVED

BUS RESET

RESERVED

76

5

4

3

2

0

1

0

0

XX

XX

X0

SV00830

Select Endpoint

Command

: 00-0Dh

Data

: Optional Read 1 byte

The Select Endpoint command initializes an internal pointer to the

start of the Selected buffer. Optionally, this command can be

followed by a data read, which returns ‘0’ if the buffer is empty and

‘1’ if the buffer is full.

76

5

4

3

2

X

1

0

0

POWER ON VALUE

FULL/EMPTY

RESERVED

XX

XX

XX

SV00831

Full/Empty

A ‘1’ indicates the buffer is full, ‘0’ indicates an

empty buffer.