Texas Instruments SPRU938B manual Read Operations

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Peripheral Architecture

2.5.2Read 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 Figure 6. The remote VLYNQ device returns the read data. Read data is shown with dotted arrows.

Figure 6. Read Operations

			System￿clock		VLYNQ￿Clock
							Serial
	Slave	Address	Outbound	Outbound		8B/10B	TxData
config￿bus				command	TxSM		Serializer
		translation	commands			encoding
	interface			FIFO
				Return
				data
				FIFO
		Registers				Local￿VLYNC
				Return
				data
				FIFO
							Serial
	Master	Address	Inbound	Inbound		8B/10B	RxData
config￿bus				command	RxSM		Deserializer
		translation	commands			decoding
	interface			FIFO
			System￿clock		VLYNQ￿Clock
							Serial
	Slave	Address	Outbound	Outbound		8B/10B	TxData
config￿bus				command	TxSM		Serializer
		translation	commands			encoding
	interface			FIFO
				Return
				data
				FIFO
		Registers				Remote￿VLYNQ
				Return
				data
				FIFO
							Serial
	Master	Address	Inbound	Inbound		8B/10B	RxData
config￿bus				command	RxSM		Deserializer
		translation	commands			decoding
	interface			FIFO
14	VLYNQ Port						SPRU938B –September 2007

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