cx28500 Mindspeed Technologies, cx28500 Datasheet - Page 141

• Manufacturer Part Number: cx28500
• Description: Cx28500 Multichannel Synchronous Communications Controller
• Manufacturer: Mindspeed Technologies

5. CX28500 writes DATA from its FIFO to the memory buffer until either an End Of Message (EOM) is stored or
6. CX28500 checks INHTBSD bit field in
7. If the Receive Buffer Descriptor contains the End Of Message (EOM), an interrupt descriptor is written in the
8. Depending on the LAST bit value set in the Receive Buffer Descriptor, CX28500 reads the next Message
7.2.2
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 into shared memory.
After the channel has been activated, channel deactivation via a service request suspends activity on an individual
channel direction. Each channel consists of a transmitter and a receiver section. Each section is independent of the
other and maintains its own state machine and configuration registers. To deactivate both transmitter and receiver
sections, two separate service requests are required, one directed to the transmitter and one to the receiver.
CX28500 may respond to each service request with the SACK Interrupt Descriptor, which notifies the Host that the
task was initiated. The notification to the Host that the task was completed is an EOCE interrupt. This
acknowledges the Host that the SRQ was completed.
7.2.2.1
The following describes what CX28500 does when transmit channel is deactivated:
1. Current message processing is terminated destructively. That is, data can be lost and messages prematurely
2. Internal FIFOs are flushed and the data is lost.
3. The TSLP is responsible for handling outbound bits when the serial port is asynchronously disabled. The data
4. The transmit channel remains in the suspended state until the channel is activated. The current channel
7.2.2.2
The following describes what CX28500 does when receive channel is deactivated:
1. Current message processing is terminated destructively. That is, data can be lost and messages prematurely
2. Internal FIFOs are flushed, and all data is lost.
3. The RSLP is responsible for handling inbound bits when the serial port is asynchronously disabled. Data
28500-DSH-002-C
the entire memory buffer (BLEN) is filled.
Buffer Descriptor with a Buffer Status Descriptor), it overwrites the Receive Buffer Descriptor. If the message
ended (i.e., EOM is set in the Receive Buffer Status Descriptor), go to step 7. If the EOM is not set in Receive
Buffer Status, it might generate an EOB interrupt depending on EOBIEN bit setting in the Receive Buffer
Descriptor. Go to step 8.
shared memory depending on the mask interrupt status.
Descriptor. Go to step 4.
aborted. CX28500 does not give any indication of a lost message. If a Message Descriptor is in the middle of
processing, it is left as it is.
output pin, TDAT, is held at logic 1. Data transfers from shared memory are halted.
direction configuration is maintained.
aborted. CX28500 gives no indication of the lost messages. If a Message Descriptor is in the middle of
processing, it is left as it is.
transfers to shared memory are halted.
Channel Deactivation
Transmit Channel Deactivation
Receive Channel Deactivation
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Section
6.6.4. If INHTBSD = 0 (i.e., CX28500 is allowed to overwrite
®
Functional Description
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