ISL78610 Datasheet, PDF (55/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
EXAMPLE NON-DAISY COMMUNICATIONS
Examples of the various command structures for non-daisy chain
installations are shown in Figures 64A through 64E.
PAGE
(14, 12)
DATA
ADDRESS
(11, 6)
TRAILING
ZEROS
(5, 0)
0011001010000000
MSB
BYTE 1
BYTE 0
LSB
FIGURE 64A. DEVICE LEVEL COMMAND: SLEEP
PAGE
(14, 12)
DATA
ADDRESS
(11, 6)
TRAILING
ZEROS
(5, 0)
0011001111000000
MSB
BYTE 1
BYTE 0
LSB
FIGURE 64B. DEVICE LEVEL COMMAND: WAKE-UP
PAGE
(14, 12)
DATA
ADDRESS
(11, 6)
TRAILING
ZEROS
(5, 0)
0011000001000000
MSB
BYTE 1
BYTE 0
LSB
FIGURE 64C. DEVICE LEVEL COMMAND: SCAN VOLTAGES
PAGE
(14, 12)
DATA
ADDRESS
(11, 6)
ELEMENT
ADDRESS
(5, 0)
0011001000000101
MSB
BYTE 1
BYTE 0
LSB
FIGURE 64D. DEVICE LEVEL COMMAND: MEASURE CELL 5 VOLTAGE
PAGE
(22, 20)
DATA
ADDRESS
(19, 14)
DATA
(13, 0)
101001001000111111111111
MSB BYTE 2
BYTE 1
BYTE 0 LSB
FIGURE 64E. DEVICE WRITE: WRITE EXTERNAL TEMPERATURE
LIMIT = 14’h0FFF
FIGURE 64. NON-DAISY CHAIN DEVICE COMMAND AND WRITE
EXAMPLES
Daisy Chain Communications
Commands in daisy chain systems are transmitted and received
via the SPI port and are composed of a device address (4 bits), a
read/write bit, page address (3 bits), data address (6 bits), data
(6 bits) and CRC (4 bits).
Device commands and data are memory mapped to 14-bit data
locations. The memory map is arranged in pages. Pages 1 and 2
are used for volatile data. Page 3 contains the action and
communications administration commands. Page 4 accesses
nonvolatile memory. Page 5 is used for factory test.
The daisy chain communication is intended for use with large
stacks of battery cells where a number of ISL78610 devices are
used.
Communications Protocol
All daisy chain communications are passed from device to device
such that all devices in the stack receive the same information.
Each device then decodes the message and responds as needed.
The originating device (master in the case of commands,
addressed device or top stack device in the case of responses)
generates the system clock and data stream. Each device delays
the data stream by one clock cycle. Each device knows its stack
location (see the Identify command on page 49). Each device
knows the total number of devices in the stack. Each originating
device adds a number of clock pulses to the daisy chain data
stream to allow transmission through the stack.
All communications from the host microcontroller are passed
from device to device to the last device in the chain (top device).
The top device responds to read and write messages with an
“ACK” (or with the requested data if this is the addressed device
and the message was a read command). The addressed device
then waits to receive the “ACK” before responding, either with
data, in the case of a read, or with an “ACK” in the case of a write.
Action commands such as the Scan commands do not require a
response.
A read or write communications transmission is only considered to
be complete following receipt of a response from the target device
or the identification of a communications fault condition. The host
microcontroller should not transmit further data until either a
response has been received from the target stack device or a
communications fault condition has been identified. A normal
daisy chain communications sequence for a stack of 10 devices:
read device 4, cell 7 data, is illustrated in Figure 65 on page 56.
The maximum response time: time from the rising edge of CS at
the end of the first byte of a read/write command, sent by the host
microcontroller, to the assertion of DATA READY by the master
device, is given in Table 24 for various daisy chain data rates.
TABLE 24. MAXIMUM RESPONSE TIMES FOR DAISY CHAIN READ AND
WRITE COMMANDS. STACK OF 10 DEVICES
MAXIMUM TIME TO ASSERTION
OF DATA READY
DAISY CHAIN DATA RATE (kHz) 500 250 125 62.5 UNIT
Response time
240 480 960 1920 µs
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June 16, 2016