Rainbow Electronics MAX34440 - Manual (Page 18)

PMBus 6-Channel Power-Supply Manager
MAX34440
18
Host Sends or Reads Too Few Bits
If for any reason the host does not complete writing a full
byte or reading a full byte from the device before a START
or STOP is received, the device does the following:
1) Ignores the command.
2) Sets the CML bit in STATUS_BYTE.
3) Sets the CML bit in STATUS_WORD.
4) Sets the DATA_FAULT bit in STATUS_CML.
5) Notifies the host through ALERT assertion (if enabled).
Host Sends or Reads Too Few Bytes
For each supported command, the device expects a
fixed number of bytes to be written or read from the
device. If for any reason fewer than the expected number
of bytes is written to or read from the device, the device
completely ignores the command and takes no action.
Host Sends Too Many Bytes or Bits
For each supported command, the device expects a
fixed number of bytes to be written to the device. If for
any reason more than the expected number of bytes or
bits is written to the device, the device does the following:
1) Ignores the command.
2) Sets the CML bit in STATUS_BYTE.
3) Sets the CML bit in STATUS_WORD.
4) Sets the DATA_FAULT bit in STATUS_CML.
5) Notifies the host through ALERT assertion (if enabled).
Host Reads Too Many Bytes or Bits
For each supported command, the device expects a fixed
number of bytes to be read from the device. If for any
reason more than the expected number of bytes or bits is
read from the device, the device does the following:
1) Sends all ones (FFh) as long as the host keeps
acknowledging.
2) Sets the CML bit in STATUS_BYTE.
3) Sets the CML bit in STATUS_WORD.
4) Sets the DATA_FAULT bit in STATUS_CML.
5) Notifies the host through ALERT assertion (if enabled).
Host Sends Improperly Set Read Bit
in the Slave Address Byte
If the device receives the R/W bit in the slave address
set to one immediately preceding the command code,
the device does the following (note this does not apply
to ARA):
1) ACKs the address byte.
2) Sends all ones (FFh) as long as the host keeps
acknowledging.
3) Sets the CML bit in STATUS_BYTE.
4) Sets the CML bit in STATUS_WORD.
5) Sets the DATA_FAULT bit in STATUS_CML.
6) Notifies the host through ALERT assertion (if enabled).
Unsupported Command Code Received
If the host sends the device a command code that it
does not support, or if the host sends a command code
that is not supported by the current PAGE setting, the
device does the following:
1) Ignores the command.
2) Sets the CML bit in STATUS_BYTE.
3) Sets the CML bit in STATUS_WORD.
4) Sets the COMM_FAULT bit in STATUS_CML.
5) Notifies the host through ALERT assertion (if enabled).
Invalid Data Received
The device checks the PAGE, OPERATION, and
WRITE_PROTECT command codes for valid data. If
the host writes a data value that is invalid, the device
does the following:
1) Ignores the command.
2) Sets the CML bit in STATUS_BYTE.
3) Sets the CML bit in STATUS_WORD.
4) Sets the DATA_FAULT bit in STATUS_CML.
5) Notifies the host through ALERT assertion (if enabled).
Alert Response Address (ARA) Byte Format
1 7 1 1 8 1 1
S
ARA
0001100
R A
DEVICE SLAVE ADDRESS
WITH LSB = 0
NA P