isp1160 NXP Semiconductors, isp1160 Datasheet - Page 23

• Manufacturer Part Number: isp1160
• Description: Isp1160 Embedded Universal Serial Bus Host Controller
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 13963
Product data
The actual requirement for the buffer RAM needs to reach not the maximum size. You
can make your selection based on your application.
The following are some calculations of the ISO_A or ISO_B space for a frame of data:
When the embedded system wants to initiate a transfer to the USB bus, the data
needed for one frame is transferred to the ATL buffer or the ITL buffer. The
microprocessor detects the buffer status through interrupt routines. When the
HcBufferStatus register (2CH to read only) indicates that the buffer is empty, then the
microprocessor writes data into the buffer. When the HcBufferStatus register
indicates that the buffer is full, the data is ready on the buffer, and the microprocessor
needs to read data from the buffer.
For every 1 ms, there might be many events to generate interrupt requests to the
microprocessor for data transfer or status retrieval. However, each of the interrupt
types defined in this specification can be enabled or disabled by setting
Hc PInterruptEnable register bits accordingly.
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Fig 17. HC internal FIFO buffer RAM partitions.
ATL buffer length
This is insufficient use of the internal FIFO buffer RAM.
ATL buffer length
This will use the internal FIFO buffer RAM for only ATL transfers.
Maximum number of useful data sent during one USB frame is 1280 bytes (20 ISO
packets of 64 bytes). The total RAM size needed is:
20
Maximum number of packets for different endpoints sent during one USB frame is
150 (150 ISO packets of 1 byte). The total RAM size needed is:
150
The Ping buffer RAM (ITL0) and the Pong buffer RAM (ITL1) have a maximum size
of 2 kbytes each. All data needed for one frame can be stored in the Ping or the
Pong buffer RAM.
8
8
1280
150
ATL buffer
ITL buffer
Rev. 05 — 24 December 2004
1
1440 bytes.
400H, ITL buffer length
1000H, ITL buffer length
bottom
1350 bytes.
ITL0
ITL1
ATL
top
control/bulk/interrupt
FIFO buffer RAM
ISO_A
ISO_B
not used
data
200H.
MGT950
0H.
Embedded USB Host Controller
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
4 kbytes
programmable
sizes
ISP1160
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