CN8478 Datasheet, PDF (137/221 Pages) Conexant Systems, Inc – Multichannel Synchronous Communications Controller (MUSYCC)

CN8478/CN8474A/CN8472A/CN8471A
Multichannel Synchronous Communications Controller (MUSYCC™)
6.0 Basic Operation
6.1 Reset
6.1.3 Soft Group Reset
Every supported channel group within MUSYCC has the ability to reset (or
deactivate) a specific direction for all channels in the group using a single service
request: the soft group reset service request.
When a soft group reset is requested, a direction (either transmit or receive) is
specified in the request, and all channels in the specified group and direction are
deactivated. For the transmit direction, output signal TDAT is three-stated.
The host must allow two line clock periods of the clock connected to the
associated serial port to elapse for this reset to complete before issuing another
service request.
When a soft group reset is requested by the host, the service request
mechanism is used. Normally, every service request is acknowledged by
MUSYCC with a SACK Interrupt Descriptor. In this case, the host should follow
up the reset request with a Global Initialization service request.
6.1.4 Initialization Sequence Example
The typical power-up or reset initialization sequence is as follows:
1. PCI configuration.
2. Soft Chip Reset.
3. Allocate Shared Memory.
4. Initialize Shared Memory Channel Group Descriptors and time slot map.
5. Write the Group Base Pointer values.
6. Allocate interrupt queue and initialize it.
7. Set Message Descriptor pointers.
8. Perform Global Initialization, waiting for SACK.
9. Perform Group Initialization, waiting for SACK between each service
request.
– Group Initialization - Receive Group 0–8
– Group Initialization - Transmit Group 0–8
NOTE: SACK for Global Initialization is not written until the Global and Interrupt
Queue Descriptors are read from memory.
100660E
Conexant
6-3