MAX11068EVKIT+ Maxim Integrated Products, MAX11068EVKIT+ Datasheet - Page 64

• Manufacturer Part Number: MAX11068EVKIT+
• Description: KIT SMART BATT MEASUREMENT 12CH
• Manufacturer: Maxim Integrated Products

Specifications of MAX11068EVKIT+

• Main Purpose: Power Management, Battery Monitor, Car
• Utilized Ic / Part: MAX11068
• Primary Attributes: Monitors Current, Voltage, Temperature
• Secondary Attributes: 1 ~ 12 Cell- Li-Ion, 1 ~ 12 Cell- NiMH
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Embedded: -

12-Channel, High-Voltage Sensor, Smart
Data-Acquisition Interface
This command is used to retrieve register information
from the stack of devices and it is the only way to read
register values (except for the ADDRESS register, which
is handled by the ROLLCALL command). After sending
the I
with the R/Wb bit low and then the command byte, the
READALL format requires a repeated start to change
the direction of data flow. Following the repeated start,
another broadcast address byte is sent with the R/Wb
bit, this time set for a read. This starts the flow of device
data back to the host. The data stream as viewed at
the lower port interface of the first device in the stack
appears as shown in Figure 39.
After the first device receives the READALL command, it
begins to send the requested register data, low byte first,
on the bus toward the host. Approximately 1Fs later, the
next device in the SMBus ladder receives the READALL
command and sends its data to the upper port of the
first device. The first device holds these bits until it is
done sending its own data and receives an acknowledge
Figure 39. I
64
SCL
SDA
SCL
SDA
SCL
SDA
SCL
SDA
SCL
SDA
2
C address byte containing the broadcast address
S
B7
2
C Communication Sequence for the ROLLCALL Command as Viewed by the Host Controller
B6
SEQUENCE REPEATS. TWO BYTES ARE RETURNED FOR EVERY DEVICE IN THE STACK.
B5
DEVICE ADDRESS N
DEVICE ADDRESS 1
DEVICE ADDRESS 2
B4
0xFF
B3
B2
READALL Command
B1
W
A
A
A
A
A
0
0
0
LAST ADDRESS
LAST ADDRESS
LAST ADDRESS
0
0xFF
0
bit, at which time it forwards the data from the second
device. This process continues for each MAX11068 in
the SMBus ladder. Because of the way the data is shifted
from each device back toward the host, the module-to-
module communication delays are effectively masked
and the host sees a continuous stream of data once the
first device receives the READALL command.
After the last device sends its data, it creates a data
check byte and PEC byte since it knows it is the last
device in the chain. The PEC byte generated by the
MAX11068 uses a CRC-8 algorithm, which is what the
host should use on the sent data. Each link of the SMBus
ladder contains a unique data sequence. Therefore,
each READALL communication between modules has
a different PEC byte. The data check byte informs the
host whether the entire communication succeeded
by passing a flag containing the PEC error status of
the entire READALL command down the chain. This
makes it easier for the host controller to determine if
the READALL command was successful without hav-
ing to check the ALRTPEC status of each module in the
0
0
1
A
A
A
A
A
SR
P
B7
B6
B5
NOTE: THE I
BYTES AT A TIME UNTIL THE TERMINATING
SEQUENCE 0xFF 0xFF IS SEEN. IT THEN
NACKS AND ISSUES A STOP CONDITION.
B4
2
C MASTER KEEPS READING 2
B3
B2
B1
R
A