Philips Semiconductors
PDIUSBD12
USB interface device with parallel bus
9. Main endpoint
The main endpoint (endpoint number 2) is the primary endpoint for sinking or
sourcing relatively large amounts of data. It implements the following features to ease
this task:
•
Double buffering. This allows parallel operation between USB access and local
CPU access thus increasing throughput. Buffer switching is handled automatically.
This results in transparent buffer operation.
•
DMA (Direct Memory Access) operation. This can be interleaved with normal I/O
operation to other endpoints.
•
Automatic pointer handling during DMA operation. No local CPU intervention is
necessary when ‘crossing’ the buffer boundary.
•
Configurable endpoint for either isochronous transfer or non-isochronous (bulk and
interrupt) transfer.
10. Command summary
Table 4:
Name
Initialization commands
Set Address/Enable
Set Endpoint Enable
Set mode
Set DMA
Data flow commands
Read Interrupt Register
Select Endpoint
Device
Control OUT
Control IN
Endpoint 1 OUT
Endpoint 1 IN
Endpoint 2 OUT
Endpoint 2 IN
Read Last Transaction Status
Control OUT
Control IN
Endpoint 1 OUT
Endpoint 1 IN
Endpoint 2 OUT
Endpoint 2 IN
Read Buffer
Write Buffer
Selected Endpoint
Selected Endpoint
F4
00
01
02
03
04
05
40
41
42
43
44
45
F0
F0
Read 2 bytes
Read 1 byte (optional)
Read 1 byte (optional)
Read 1 byte (optional)
Read 1 byte (optional)
Read 1 byte (optional)
Read 1 byte (optional)
Read 1 byte
Read 1 byte
Read 1 byte
Read 1 byte
Read 1 byte
Read 1 byte
Read n bytes
Write n bytes
Device
Device
Device
Device
D0
D8
F3
FB
Write 1 byte
Write 1 byte
Write 2 bytes
Write/Read 1 byte
Command summary
Destination
Code (Hex)
Transaction
9397 750 09238
© Koninklijke Philips Electronics N.V. 2001. All rights reserved.
Product data
Rev. 08 — 20 December 2001
10 of 35
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