28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 141

• 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

6.3.16
After the previous levels of configuration are completed, individual channels within a channel group are ready to be
activated. Service requests activate channels.
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, configuration registers, and internal resources. To activate 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, notifying the
host that the task was completed.
Channel Activation is an asynchronous command from the host interface to a transmit or receive section of a
channel to jump to a new message. Message Descriptors in shared memory describe the attributes of the new
28478-DSH-002-E
pTxMsgDescr[1]->pNextMsgDescr = pTxMsgDescr[2];
pTxMsgDescr[2]->pNextMsgDescr = pTxMsgDescr[3];
pTxMsgDescr[3]->pNextMsgDescr = pTxMsgDescr[0];
/* Note: last descriptor points to itself */
/* assign each message descriptor a data buffer */
pTxMsgDescr[0]->pDataBuffer[0] = pDataBuf[0];
pTxMsgDescr[1]->pDataBuffer[1] = pDataBuf[1];
pTxMsgDescr[2]->pDataBuffer[2] = pDataBuf[2];
pTxMsgDescr[3]->pDataBuffer[3] = pDataBuf[3];
/* set the value for each buffer descriptor in each message descriptor */
/* OWNER bit to MUSYCC, for tx buffers set to 1, for rx set to 0 */
/* NP bit to enable polling, set to 0 */
/* EOM bit if the last data buffer is associated with this descriptor */
/* EOBI bit to enable end-of-buffer interrupt, set to 1 */
/* IC field to set the idle-code to 7Eh, set to 0 */
/* PADEN field to disable pad fill, set to 0 */
/* PADCNT field to specify 0 pad fill codes, set to 0 */
/* REPEAT bit to disable message retransmission, set to 0 */
/* BLEN field set to the length of the data buffer, set to 256 */
/* msg descr 0 */
pTxMsgDescr[0]->BufferDescr = 0x90000200;
/* msg descr 1 */
pTxMsgDescr[1]->BufferDescr = 0x90000200;
/* msg descr 2 */
pTxMsgDescr[2]->BufferDescr = 0x90000200;
/* msg descr 3 */
/* only difference is EOM bit */
pTxMsgDescr[3]->BufferDescr = 0x92000200;
/* fill data buffer with outbound traffic. each buffer contains 256-bytes of data */
/* set the head pointer, for example for channel 0, to point to the top of */
/* the just formed message descriptor list */
/* activate transmit channel by issuing a service request */
/* ServiceRequest( ACTIVATE_CHANNEL, Group, Channel, Direction ); */
Channel Activation
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