ISP1362
Single-chip USB OTG controller
Philips Semiconductors
placed in the ATL RAM at the same time. A paired PTD is designed specially for
high performance of a single endpoint. They are identified by hardware by using
the ‘Paired’ bit in the PTD.
• Possible to send up to a maximum of 18 USB bulk packets in 1 ms frame
(1.152 Mbyte/s) by using the paired PTD feature.
• Provides the status of every transfer endpoints (PTD) by monitoring the
HcATLDoneMap of the ISP1362. This register provides information on which PTD
transfers are complete.
• Sets the IRQ after the user-specified number of transfers is done.
• Skips any PTD that is wasting bandwidth by using HcATLSkipMap.
12.5.1 Sending a USB device request (Get Descriptor)
This section provides an example on how a USB transfer descriptor ‘Get Descriptor’
(commonly used in device enumeration) is used to illustrate the ISP1362 PTD
application. To perform this example, make sure the ISP1362 is in the Operational
state, and then connect a USB device (for example, a USB mouse) to a port.
Remark: For details on the USB device request, refer to Chapter 9 of Universal Serial
Bus Specification Rev. 2.0.
Step 1: Set the HcATLBlockSize, HcATLSkip and HcATLLast registers to 0x0008,
0xFFFE and 0x0001, respectively.
Step 2: A PTD is then constructed based on the information given in the following
sample code. This sample code places information into the correct bit location within
the 8 bytes of the PTD structure.
ActualBytes (10 bits) = 0x00
CompletionCode (4 bits) = 0x0F
Active (1 bit) = 1
Toggle (1 bit) = 0
MaxPacketSize (10 bits) = 8
EndpointNumber (4 bits) = 0
Speed (1 bit) = 0 (full-speed; use 1 for low-speed)
DirToken (2 bits) = 0 (setup token)
TotalBytes (10 bits) = 8
CompletedPTD
0xF800, 0x0008, 0x0008, 0x0000
Step 3: This array is then appended with an 8-byte payload that specifies the type of
request the HC wants to send. For example, for Get Descriptor, the payload is
0x0680, 0x0100, 0x0000, 0x0012.
Step 4: The 16 bytes of data is now a complete PTD with an accompanying payload.
This array is then copied into the ATL buffer area. Table 12 shows the ATL buffer area.
Table 12: ATL buffer area
Offset
0
1
2
3
4
5
6
7
Data
0xF800 0x0008 0x0008 0x0000 0x0680 0x0100 0x0000 0x0012
Step 5: After copying data into the ATL buffer, the HC must be notified that the ATL
buffer is now full and ready to be processed. The ATL_Active bit of the
HcBufferStatus register must be set to logic 1 to inform the HC that the data in the
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© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
Product data
Rev. 03 — 06 January 2004
45 of 150
NXP [ NXP ]
