ISP1181BBSUM STEricsson, ISP1181BBSUM Datasheet - Page 32

• Manufacturer Part Number: ISP1181BBSUM
• Manufacturer: STEricsson

Specifications of ISP1181BBSUM

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / RoHS Status: Compliant

CD00222684
Product data sheet
12.2.1 Write/Read Endpoint Buffer
12.2 Data flow commands
Data flow commands are used to manage the data transmission between the USB
endpoints and the system microcontroller. Much of the data flow is initiated via an interrupt
to the microcontroller. The data flow commands are used to access the endpoints and
determine whether the endpoint FIFOs contain valid data.
Remark: The IN buffer of an endpoint contains input data for the host, the OUT buffer
receives output data from the host.
This command is used to access endpoint FIFO buffers for reading or writing. First, the
buffer pointer is reset to the beginning of the buffer. Following the command, a maximum
of (N + 2) bytes can be written or read, N representing the size of the endpoint buffer. For
16-bit access the maximum number of words is (M + 1), with M given by (N + 1) DIV 2.
After each read/write action the buffer pointer is automatically incremented by 1 (8-bit bus
width) or by 2 (16-bit bus width).
In DMA access the first 2 bytes or the first word (the packet length) are skipped: transfers
start at the third byte or the second word of the endpoint buffer. When reading, the
ISP1181B can detect the last byte/word via the EOP condition. When writing to a
bulk/interrupt endpoint, the endpoint buffer must be completely filled before sending the
data to the host. Exception: when a DMA transfer is stopped by an external EOT
condition, the current buffer content (full or not) is sent to the host.
Remark: Reading data after a Write Endpoint Buffer command or writing data after a
Read Endpoint Buffer command data will cause unpredictable behavior of ISP1181B.
Code (Hex): 01 to 0F — write (control IN, endpoint 1 to 14)
Code (Hex): 10, 12 to 1F — read (control OUT, endpoint 1 to 14)
Transaction — write/read maximum (N + 2) bytes (isochronous endpoint: N ≤ 1023,
bulk/interrupt endpoint: N ≤ 32)
The data in the endpoint FIFO must be organized as shown in
endpoint FIFO access are given in
Table 28.
Byte #
(8-bit bus)
0
1
2
3
…
(N + 1)
Endpoint FIFO organization
Word #
(16-bit bus)
0 (lower byte)
0 (upper byte)
1 (lower byte)
1 (upper byte)
…
M = (N + 1) DIV 2
Rev. 05 — 25 August 2010
Table 29
Description
packet length (lower byte)
packet length (upper byte)
data byte 1
data byte 2
…
data byte N
(8-bit bus) and
Full-speed USB peripheral controller
Table 30
Table
© ST-ERICSSON 2010. All rights reserved.
28. Examples of
(16-bit bus).
ISP1181B
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