Read Operations - Texas Instruments SPRU938B User Manual

Peripheral Architecture
2.5.2

Read Operations

Read requests from the slave configuration bus interface are written to the outbound CMD FIFO (similar to
the write requests). Data is subsequently read from the FIFO and encapsulated into a read request
packet. The packet is encoded and serialized before it is transmitted to the remote device. Next, the
remote device deserializes, decodes the receive data, and writes the receive data to the inbound CMD
FIFO. After reading the address from the FIFO, a master configuration bus interface read operation
initiates in the remote device. When the remote master configuration bus interface receives the read data,
the data is written to the return data FIFO before it is encoded and serialized. When the receive data
reaches the local VLYNQ module, it is deserialized, decoded, and written to the return data FIFO (local
device). Finally, the read data is transferred on the local device's slave configuration interface.
The data flow between two connected VLYNQ devices with read requests that originate from the DM643x
device is shown in
dotted arrows.
Slave
Address
config bus
translation
interface
Registers
Master
Address
config bus
translation
interface
Slave
Address
config bus
translation
interface
Registers
Master
Address
config bus
translation
interface
14 VLYNQ Port
Figure 6. The remote VLYNQ device returns the read data. Read data is shown with
Figure 6. Read Operations
System clock
Outbound
Outbound
command
commands
FIFO
Return
data
FIFO
Return
data
FIFO
Inbound
Inbound
command
commands
FIFO
System clock
Outbound
Outbound
command
commands
FIFO
Return
data
FIFO
Return
data
FIFO
Inbound
Inbound
command
commands
FIFO
VLYNQ Clock
8B/10B
TxSM
encoding
Local VLYNC
8B/10B
RxSM
decoding
VLYNQ Clock
8B/10B
TxSM
encoding
Remote VLYNQ
8B/10B
RxSM
decoding
www.ti.com
Serial
TxData
Serializer
Serial
RxData
Deserializer
Serial
TxData
Serializer
Serial
RxData
Deserializer
SPRU938B – September 2007
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