Motorola MVME172 - Manual (Page 80)

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VMEchip2
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❏ VMEbus Bus to Local Bus Interface:
– Programmable VMEbus map decoder.
– Programmable AM decoder.
– Programmable local bus snoop enable.
– Simple VMEbus to local bus address translation.
– 8-bit, 16-bit and 32-bit VMEbus data width.
– 8-bit, 16-bit and 32-bit block transfer.
– Standard and extended VMEbus addressing.
– Software-enabled write posting mode.
– Write post buffer (17 four-bytes in BLT mode, two four-bytes in
non-BLT mode).
– An eight four-byte read ahead buffer (BLT mode only).
❏ 32-bit Local to VMEbus DMA Controller:
– Programmable 16-bit, 32-bit, and 64-bit VMEbus data width.
– Programmable short, standard, and extended VMEbus
addressing.
– Programmable AM code.
– Programmable local bus snoop enable.
– A 16 four-byte FIFO data buffer.
– Supports up to 4 GB of data per DMA request.
– Automatically adjusts transfer size to optimize bus utilization.
– DMA complete interrupt.
– DMAC command chaining is supported by a singly-linked list of
DMA commands.
– VMEbus DMA controller requester:
Software-enabled fair request modes;
Software-configured release modes:
Release-On-Request (ROR), and
Release-On-End-Of-Data (ROEOD);
Software-configured BR0-BR3 request levels; and
Software enabled bus-tenure timer.