28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 143

• Manufacturer Part Number: 28478G-18
• Description: Multichannel Synchronous Communications Controller 208-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of 28478G-18

• Package: 208BGA
• Maximum Data Rate: 32768 Kbps
• Transmission Media Type: Wire
• Power Supply Type: Analog
• Typical Supply Current: 250 mA
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V
• Maximum Operating Supply Voltage: 3.6 V

5. At end of message, Interrupt Descriptors and Buffer Status Descriptors can be written out to shared memory
6. Read Next Message Descriptor.
7. Go to 3.
6.3.17
After the channel has been activated, channel deactivation via a service request suspends activity on an individual
channel-direction by stopping that channel’s processing of the current buffer list. The only indication that MUSYCC
has completely stopped its list processing is a SACK interrupt. Therefore, the host must wait for a SACK before
setting up the new buffer list.
Each channel within a channel group consists of a transmitter and 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. MUSYCC responds to each service request with the SACK Interrupt Descriptor, which notifies the host
that the task was completed.
A channel deactivation is an asynchronous command from the host interface to a transmit or receive section of a
channel to suspend bit-level processing and halt memory transfers into shared memory.
6.3.17.1
The following describes what MUSYCC does when the transmit channel is deactivated:
1. Current message processing is terminated destructively; that is, data can be lost and messages prematurely
2. The bit-level processor responsible for handling outbound bits to the serial port is immediately and
3. The channel direction remains in the suspended state until the channel is activated. The current channel
28478-DSH-002-E
If INHRBSD = 1 (i.e., MUSYCC is not allowed to overwrite Buffer Descriptor), the address of Next Message
Pointer is pre-fetched from the current Message Descriptor and stored in the Message Pointer slot in shared
memory. After the current message is completely processed, MUSYCC jumps to this pointer and starts
processing the new message. Go to 5 when current message is processed, otherwise repeat 4.
Simultaneously, the receiver is configured and data is sampled in from the serial port using control lines RCLK,
RSYNC, RDAT, and ROOF as appropriate, and, MUSYCC masters the PCI bus and transfers data from the
internal FIFO to shared memory.
(see 3)—depending on the masking of interrupts and allowance of Buffer Descriptor overwrites.
aborted.
asynchronously disabled. The data output pin, TDAT, is three-stated or held at logic 1, depending on the bit
field TRITX in the Port Configuration Descriptor. Data transfers from shared memory are halted.
direction configuration is maintained.
NOTE:
Channel Deactivation
Transmit Channel Deactivation
Preliminary Information / Mindspeed Proprietary and Confidential
MUSYCC responds to either a JUMP or ACTIVATE service request by reading first the head
pointer and then the Message Descriptor pointed to by the Head Pointer. Therefore,
software must set up the new head pointer and Message Descriptors (i.e., buffer list)
before issuing either a JUMP or ACTIVATE service request.
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Basic Operation
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