Intel C2518 FH8065501516710 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

Datasheet, Vol. 2 of 3

September 2014

298

Order Number: 330061-002US

The hardware will ACK all valid transactions above. An exception is when processing 

the Assign Address protocol, if the received UDID does not match any internal UDID 

the hardware begins NACKing after the first unmatched byte. Another exception is that 

if the Address Resolved flag is asserted and a Get UDID (general) command is received, 

the command byte is NACKed. Finally, a PEC failure causes a transaction to be NACKed.

In both directed protocols, Get UDID (directed) and Reset Device (directed), the 

second byte, or ARP command byte, consists of the target slave address with an 

appended 0 or 1 to denote a Reset Device or Get UDID protocol, respectively. 

Therefore, the hardware uses address bits [7:1] for address comparison and LSB bit 0 

to determine the protocol.

Since the SMT supports multiple UDIDs, during the ARP process it participates in the 

Get UDID (general) and Assign Address protocols once for each UDID such that each 

UDID has a slave address which is resolved by the ARP master.

For GPBR and all both Get UDID flavors, the transaction is descriptor-only with no 

target data written to memory, and the descriptor is managed by the hardware.

The firmware implements a time-out mechanism such that if the SoC issues the Notify 

ARP Master command and the ARP Master does not respond within a particular time 

period then the SoC re-issues the Notify ARP Master command. It is implemented to 

comply with SMBus 2.0 Specification for bus timing.

Ordinary SMBus protocol

Ordinary SMBus protocol

T

n/a

9,10,11

Normal hardware-firmware flow

SMBus block-read

T

n/a

9,10,11

The hardware returns the specified number of bytes 

from the hardware buffers.

ARP protocol

Prepare to ARP 

n/a

n/a

12,13

Normal hardware-firmware flow

Reset Device (general)

n/a

n/a

12,14,15

Normal hardware-firmware flow

Assign Address

n/a

n/a

12,14,16,

17,18

Normal hardware-firmware flow

Get UDID (general)

n/a

T

12,14,16,

19,21

The hardware does NACK the ARP command byte to 

indicate it has a valid assigned slave address (ARP is 

complete).

Get UDID (general)

T

F

12,14,16,

19,21,22,

23,24

The hardware returns its UDID and corresponding 

Slave Address.

Get UDID (general)

F

F

12,14,16,

19,21,22,

23,25

The hardware returns its UDID and 0xFF for its 

address.

Reset Device (directed)

T

n/a

12,14,15,

19,20,26,

15

Normal hardware-firmware flow

Get UDID (directed)

T

n/a

12,14,16,

19,20,26,

27,29

The hardware returns its UDID and corresponding 

Slave Address.

None of the above ARP 

protocols

n/a

n/a

12,14,16,

19,20,26,

27,28

Normal hardware-firmware flow
(error handling situation)