CN8478 Datasheet, PDF (94/221 Pages) Conexant Systems, Inc – Multichannel Synchronous Communications Controller (MUSYCC)

5.0 Memory Organization
5.1 Memory Architecture
CN8478/CN8474A/CN8472A/CN8471A
Multichannel Synchronous Communications Controller (MUSYCC™)
Next, the host allocates the required shared memory for transmit and receive
messages. Assume, for example, the host needs 8 message descriptors for each
channel and direction, and each corresponding data buffer per message is 100h
(256) bytes in length.
Memory for Message Descriptors =
32 channels/group *
2 directions/channel *
12 bytes/message descriptor *
8 buffers/channel
= 1800h bytes/group
= 6144 bytes/group
Memory for Data Buffers =
32 channels/group *
2 directions/channel *
8 buffers/channel *
256 bytes/buffer
= 131, 072 bytes/group
= 20,000h bytes/group
Further, the host may choose to allocate all the memory contiguously, or it
may allocate the memory for message descriptors separately from data buffers. In
this case, message descriptors for 8 Channel Groups may be merged into a
contiguous block of memory [(1800h x 8 = C000h) bytes in length].
5-8
Conexant
100660E