ISP1181A Просмотр технического описания (PDF) - Philips Electronics
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ISP1181A Datasheet PDF : 70 Pages
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Philips Semiconductors
ISP1181A
Full-speed USB peripheral controller
Short packet: Normally, the transfer byte count must be set via a control endpoint
before any DMA transfer takes place. When a short packet has been enabled as EOT
indicator (SHORTP = 1), the transfer size is determined by the presence of a short
packet in the data. This mechanism permits the use of a fully autonomous data
transfer protocol.
When reading from an OUT endpoint, reception of a short packet at an OUT token
will stop the DMA operation after transferring the data bytes of this packet.
Table 10: Summary of EOT conditions for a bulk endpoint
EOT condition
OUT endpoint
IN endpoint
EOT input
EOT is active
EOT is active
DMA Counter Register
transfer completes as
programmed in the DMA
Counter register
transfer completes as
programmed in the DMA
Counter register
Short packet
short packet is received and counter reaches zero in the
transferred
middle of the buffer
DMAEN bit in DMA
Configuration Register
DMAEN = 0[1]
DMAEN = 0[1]
[1] The DMA transfer stops. However, no interrupt is generated.
10.4.2 Isochronous endpoints
A DMA transfer to/from an isochronous endpoint can be terminated by any of the
following conditions (bit names refer to the DMA Configuration Register, see
Table 24):
• An external End-Of-Transfer signal occurs on input EOT
• The DMA transfer completes as programmed in the DMA Counter register
(CNTREN = 1)
• An End-Of-Packet (EOP) signal is detected
• DMA operation is disabled by clearing bit DMAEN.
Table 11: Recommended EOT usage for isochronous endpoints
EOT condition
OUT endpoint
IN endpoint
EOT input active
do not use
preferred
DMA Counter Register zero do not use
preferred
End-Of-Packet
preferred
do not use
9397 750 13959
Product data
Rev. 05 — 08 December 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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