Philips Semiconductors
PDIUSBD12
USB interface device with parallel bus
operation before the data is sent to the host. The only exception is at the end of DMA
transfer, when the reception of pin EOT_N will stop DMA write operation and the
buffer content will be sent to the host on the next IN token.
For isochronous transfers, the local CPU and DMA controller have to guarantee that
they are able to sink or source the maximum packet size in one USB frame (1 ms).
The assertion of pin DMACK_N automatically selects the main endpoint (endpoint 2),
regardless of the current selected endpoint. The DMA operation of the PDIUSBD12
can be interleaved with normal I/O access to other endpoints.
DMA operation can be terminated by resetting the DMA enable register bit or the
assertion of EOT_N together with DMACK_N and either RD_N or WR_N.
The PDIUSBD12 supports DMA transfer in single address mode and it can also work
in dual address mode of the DMA controller. In the single address mode, DMA
transfer is done via the DREQ, DMACK_N, EOT_N, WR_N and RD_N control lines.
In the dual address mode, pins DMREQ, DMACK_N and EOT_N are
not
used;
instead CS_N, WR_N and RD_N control signals are used. The I/O mode Transfer
Protocol of PDIUSBD12 needs to be followed. The source of the DMAC is accessed
during the read cycle and the destination during the write cycle. Transfer needs to be
done in two separate bus cycles, storing the data temporarily in the DMAC.
8. Endpoint description
The PDIUSBD12 endpoints are sufficiently generic to be used by various device
classes ranging from Imaging, Printer, Mass Storage and Communication device
classes. The PDIUSBD12 endpoints can be configured for 4 operating modes
depending on the Set mode command. The 4 modes are:
Mode 0
Mode 1
Mode 2
Mode 3
Non-isochronous transfer (Non-ISO mode)
Isochronous output only transfer (ISO-OUT mode)
Isochronous input only transfer (ISO-IN mode)
Isochronous input and output transfer (ISO-I/O mode).
9397 750 09238
© Koninklijke Philips Electronics N.V. 2001. All rights reserved.
Product data
Rev. 08 — 20 December 2001
8 of 35
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