Intel C2350 FH8065401488914 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

Datasheet, Vol. 2 of 3

September 2014

300

Order Number: 330061-002US

The ARP Master must always execute the ARP when it enters the working state and 

anytime it receives an SMBus status change indication (due to device addition or 

removal). The process begins with the ARP Master issuing the Prepare To ARP 

command. In all cases the ARP Master must be able to resolve addresses when it 

receives the Notify ARP Master command.

Since SMBus devices join the system without a corresponding system reset (i.e., a hot-

plug event), the ARP Master optionally chooses to issue the Get UDID (general) 

command at least once every 10 seconds to discover newly added devices that require 

address resolution but which do not support the Notify ARP Master command. No 

device whose AR flag is set responds to this command. However, a newly added device 

enters the system with a power-up reset, which resets its AR flag; it responds to a Get 

UDID (general) command with its UDID. The host chooses to assign such a newly 

added device a non-conflicting address or chooses to re-ARP the entire bus.

Until the ARP process is complete the ARP Master must not wait more than tow seconds 

before issuing a Get UDID (general) command after issuing the previous Get UDID 

(general) command. This restriction is important to allow another SMBus master to 

determine when it is safe to do an enumeration of the bus.

With reference to 

 the ARP Master operates as follows (steps which are 

shaded are the responsibility of the firmware alone or of the firmware to trigger the 

hardware, or vice versa).

0. . . Perform ARP master initialization.

• [FW]  See 

1.

Upon starting, the ARP Master initializes its Used Address Pool. Initially 

this consists of the slave addresses of fixed-address SMBus devices 

known to the ARP Master and reserved addresses (as defined in SMBus 

2.0 Specification).

• [FW]

2.

Send the Prepare To ARP command.

• [FW]

3.

Check for an acknowledgement for all bytes in the previous packet. If 

any bytes were not acknowledged then the ARP Master assumes that no 

ARP-capable devices are present and therefore consider the ARP 

process complete; proceed to step 4. If all bytes were acknowledged 

then go to step 6.

• [FW]

4.

The ARP Master found no response to the Prepare To ARP command so 

it assumes that no ARP-capable devices are present in the system at 

this time. The ARP Master periodically re-issues the Prepare To ARP 

command to discover any ARP-capable devices added. Proceed to step 

5.

• [FW]

5.

Wait for an SMBus packet. If a packet is received proceed to step 15.

• [FW]

6.

Send the Get UDID command.

• [FW]

7.

Check for an acknowledgement for the first three bytes and verify that 

the byte count value received is 0x11. If not, then the ARP Master 

assumes that an ARP-capable device(s) is no longer present and 

therefore consider the ARP process complete; proceed to step 4. 

Otherwise proceed to step 8.

• [HW and FW] HW verifies the byte count 

before sending descriptor to FW.

8.

Check the value of the Device Slave Address received. If 0xFF then 

proceed to step 11 since this device does not possess a valid slave 

address. Otherwise proceed to step 9.

• [FW]

9.

Determine if this device has a fixed slave address. If bits 127 and 126 of 

the UDID are 00b then it has a fixed address, so proceed to step 12. 

Otherwise proceed to step 10.

• [FW]