PDIUSBD Philips Semiconductors, PDIUSBD Datasheet - Page 10

• Manufacturer Part Number: PDIUSBD
• Description: USB device with serial interface
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Clear Buffer
Command
Data
When a packet is received completely, an internal endpoint buffer
full flag is set. All subsequent packets will be refused by returning a
NAK. When the microcontroller has read the data, it should free the
buffer by the Clear Buffer command. When the buffer is cleared,
new packets will be accepted.
Validate Buffer
Command
Data
When the microprocessor has written data into an IN buffer, it should
set the buffer full flag by the Validate Buffer command. This indicates
that the data in the buffer are valid and can be sent to the host when
the next IN token is received.
Set Endpoint Status
Command
Data
A stalled control endpoint is automatically unstalled when it receives
a SETUP token, regardless of the content of the packet. If the
endpoint should stay in its stalled state, the microcontroller can
re-stall it.
When a stalled endpoint is unstalled (either by the Set Endpoint
Status command or by receiving a SETUP token), it is also
re-initialized. This flushes the buffer and if it is an OUT buffer it waits
for a DATA 0 PID, if it is an IN buffer it writes a DATA 0 PID.
Even when unstalled, writing Set Endpoint Status to ‘0’ initializes the
endpoint.
Stalled
1999 Jul 22
USB device with serial interface
X X
7
6
5
X X
A ‘1’ indicates the endpoint is stalled.
: F2h
: None
: FAh
: None
: 40–4Dh
: Write 1 byte
4
3
X X
2
1
X
0
0
POWER ON VALUE
STALLED
RESERVED
SV00834
10
Acknowledge Setup
Command
Data
The arrival of a SETUP packet flushes the IN buffer and disables the
Validate Buffer and Clear Buffer commands for both IN and OUT
endpoints.
The microcontroller needs to re-enable these commands by the
Acknowledge Setup command. This ensures that the last SETUP
packet stays in the buffer and no packet can be sent back to the
host until the microcontroller has acknowledged explicitly that it has
seen the SETUP packet.
The microcontroller must send the Acknowledge Setup command to
both the IN and OUT endpoints.
GENERAL COMMANDS
Send Resume
Command
Data
Sends an upstream resume signal for 10 ms. This command is
normally issued when the device is in suspend. The RESUME
command is not followed by a data read or write.
Read Current Frame Number
Command
Data
This command is followed by one or two data reads and returns the
frame number of the last successfully received SOF. The frame
number is returned Least Significant Byte first.
7
X X
7
X X
6
6
X X
X X
5
5
4
4
: F1h
: None
: F6h
: None
: F5h
: Read One or Two Bytes
3
3
X X
X X
2
2
1
1
X
X
0
X
0
X
LEAST SIGNIFICANT BYTE
MOST SIGNIFICANT BYTE
PDIUSBD11
Product specification
SV00835