Receive and Transmit Description

Initial State

 

 

 

 

Packet received &

 

 

 

transferred to host

 

 

Idle

memory

 

 

 

Restart Count

 

 

 

Other receive

Restart Count

 

 

timer interrupt

 

 

Running

Packet received

&

 

 

transferred to host

 

 

memory

 

Generate

Timer expires

 

 

Int

 

 

 

 

 

Figure 3-3. Packet Delay Timer Operation (State Diagram)

3.2.7.1.2Receive Interrupt Absolute Delay Timer (RADV)

The Absolute Timer ensures that a receive interrupt is generated at some predefined interval after the first packet is received. The absolute timer is started once a packet is received and transferred to host memory (specifically, after the last packet data byte is written to memory) but is NOT reinitialized / restarted each time a new packet is received. When the Absolute Timer expires (no receive interrupt has been generated for the amount of time defined in RADV) the Receive Timer Interrupt is generated.

Setting RADV to 0b or RDTR to 0b disables the Absolute Timer. To disable the Packet Timer only, RDTR should be set to RADV + 1b.

The Absolute Timer is reinitialized (but not started) when the Receive Timer Interrupt is generated due to a Packet Timer expiration or Small Receive Packet Detect Interrupt.

Software Developer’s Manual

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Intel PCI-X manual Receive Interrupt Absolute Delay Timer Radv, Packet Delay Timer Operation State Diagram