cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 156

• Manufacturer Part Number: cx28560
• Description: Hdlc Controller
• Manufacturer: Mindspeed Technologies

Functional Description
6.2.2
6.2.2.1
6.2.2.2
6.2.3
6-10
Channel Deactivation
Channel Reactivation
After the channel has been activated, channel deactivation via a service request
suspends activity on an individual channel direction. Each channel consists of a
transmit and a receive direction. Each direction is independent of the other and
maintains its own state machines and configuration registers. To deactivate both the
transmit and receive directions of a channel, two separate service requests are
required, one directed towards the transmit and one to the receive. The CX28560 may
respond to each service request with the SACK Interrupt Descriptor, which notifies
the host that the task was initiated. Note that the SACK interrupt will only be
generated if the SACKIEN bit is asserted in the Service Request Descriptor.
NOTE:
Transmit Channel Deactivation
The following describes what the CX28560 does when transmit channel is
deactivated:
NOTE:
Receive Channel Deactivation
The following describes what the CX28560 does when receive channel is deactivated:
NOTE:
Channel reactivation is not supported. To reset a channel, it must first be deactivated,
and then, once the End Of Command (EOC) interrupt has been received, activated.
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The notification to the host that the task was completed is an EOC interrupt.
This acknowledges the host that the SRQ was completed. A Channel
Deactivation is an asynchronous command from the host interface to a transmit
or receive section of a channel to suspend processing and halt memory
transfers to/from the host.
The current message processing is terminated destructively. That is, data can
be lost and messages prematurely aborted. The CX28560 does not give any
indication of a lost message directly to the host, but does increment the aborted
messages counter.
Internal FIFOs are flushed and the data is lost.
The TSLP is responsible for handling outbound bits when the serial port is
asynchronously disabled. The data output pin, TDAT, is held at logic 1. Any
data received by the CX28560 while a channel is deactivated is discarded.
The transmit channel remains in the suspended state until the channel is
activated. The current channel direction configuration is maintained.
Counters are automatically zeroed on deactivation, activation and one-second
pulses.
Current message processing is terminated destructively. That is, data can be
lost and messages prematurely aborted. The CX28560 does not give any direct
indication of the lost messages.
Internal FIFOs are flushed and all data is lost.
The RSLP is responsible for handling inbound bits when the serial port is
asynchronously disabled. Data transfers to the host are halted.
The receive channel remains in the suspended state until the channel is
activated. The current channel direction configuration is maintained.
Counters are automatically zeroed on deactivation, activation and one-second
pulses.
Mindspeed Technologies™
Advance Information
CX28560 Data Sheet
28560-DSH-001-B