Figure 6.13-18 Bus Management Packet Protocol Diagram Element Key - Nuvoton ISD94124BYI Technical Reference Manual

Bus protocols
There are eleven possible command protocols for any given device. A device may use any or all of
the eleven protocols to communicate. The protocols are Quick Command, Send Byte, Receive
Byte, Write Byte, Write Word, Read Byte, Read Word, Process Call, Block Read, Block Write
and Block Write-Block Read Process Call. These protocols should be implemented by the user
software. (For more details of these protocols, refer to SMBus specification ver. 2.0)
1
S
S
Sr
Rd
Wr
x
A
P
PEC
...

Figure 6.13-18 Bus Management Packet Protocol Diagram Element Key

Address resolution protocol (ARP)
Bus Management slave address conflicts can be resolved by dynamically assigning a new unique
address to each slave device. In order to provide a mechanism to isolate each device for the
purpose of address assignment each device must implement a unique device identifier (UDID). This
128-bit number is implemented by software.
This peripheral supports the Address Resolution Protocol (ARP). The Bus Management Device
Default Address (0b1100 001) is enabled by setting BUSEN (I2C_BUSCTL[7]), BMDEN
(I2C_BUSCTL[2]) and ALERTEN (I2C_BUSCTL[4]) bits. The ARP commands should be
implemented by the user software. Arbitration is also performed in slave mode for ARP support.
Received Command and Data acknowledge control
A Bus Management receiver must be able to NACK each received command or data. In order to
allow the ACK control in slave mode, the Slave Byte Control mode must be enabled by setting
ACKMEN bit (I2C_BUSCTL[0]).
Host Notify protocol
Sep 9, 2019
ISD94100 Series Technical Reference Manual
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SMB Host Addr Wr A
X
Start Condition
Repeated Start Condition
Read (bit value 1)
Write (bit value 0)
Shown under a field indicates that that
field is requored to have the value of'x'
Acknowledge (this bit position may be '0'
for an ACK or '1'for a NACK
Stop Condition
Packet Error Code
Master (SMBus Device) to Slave
Slave (SMBus Host) to Master
Continuation of protocol
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Data Byte A P
X
Rev1.09