ISL78610 Datasheet, PDF (44/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
VOLTAGE SCAN
765µs
512ms
WIRE SCAN
59.4ms
TEMPERATURE SCAN
2.69ms
TEMPREG PIN
Hi-Z
2.5V
Hi-Z
Hi-Z
2.5ms
ADC SAMPLING
FIGURE 59. SCAN TIMING EXAMPLE DURING SCAN CONTINUOUS MODE AND SCAN ALL MODE
Sleep Command
Sleep mode is entered in response to a Sleep command. Only the
communications input circuits, low speed oscillator and internal
registers are active in Sleep mode, allowing the part to perform
timed scan and balancing activity and to wake up in response to
communications.
Using a Sleep command does not require that the devices in a
daisy chain stack be identified first. They do not need to know
their position in the stack.
In a daisy chain system, the Sleep command must be written
using the Address All stack address. The command is not
recognized if sent with an individual device address and causes
the addressed device to respond NAK. The top stack device
responds ACK on receiving a valid Sleep command.
Having received a valid Sleep command, devices wait before
entering the Sleep mode. This is to allow time for the top stack
device in a daisy chain to respond ACK, or for all devices that
don’t recognize the command to respond NAK, and for the host
microcontroller to respond with another command. Receipt of
any valid communications on Port 1 of the ISL78610 before the
wait period expires cancels the Sleep command. Receipt of
another Sleep command restarts the wait timers. Table 13
provides the maximum wait time for various daisy chain data
rates. The communications fault checking timeout is not applied
to the Sleep command. A problem with the communications is
indicated by a lack of response to the host microcontroller. The
host microcontroller may choose to do nothing if no response is
received, in which case, devices that received the Sleep
command go to sleep when the wait time expires. Devices that
do not receive the message go to sleep when their watchdog
timer expires (as long as this is enabled).
Devices exit Sleep mode on receipt of a valid Wake-up command.
TABLE 13. MAXIMUM WAIT TIME FOR DEVICES ENTERING SLEEP MODE
MAXIMUM WAIT TIME FROM
TRANSMISSION OF SLEEP COMMAND
(DAISY CHAIN ONLY)
DAISY CHAIN DATA RATE (kHz) 500 250
125
62.5
Time to Enter Sleep mode (µs) 500 1000 2000 4000
Wake Command
The communications pins are monitored when the device is in
Sleep mode, allowing the part to respond to communications.
The host microcontroller wakes up a sleeping device, or a stack
of sleeping devices, by sending the Wake-up command to a
stand-alone or a master stack device. In a daisy chain
configuration, the Wake-up command must be written using the
Address All stack address. The command is not recognized if
sent with an individual device address and causes the master
device to respond NAK.
Using a Wake-up command does not require that the devices in a
stack be identified first. They do not need to know their position
in the stack.
The master exits Sleep mode on receipt of a valid Wake-up
command and proceeds to transmit the Wake-up signal to the next
device in the stack. The Wake-up signal is a few cycles of a 4kHz
clock. Each device in the chain wakes up on receipt of the Wake-
up signal and proceeds to send the signal onto the next device.
Any communications received on Port 1 by a device which is
transmitting the Wake-up signal on Port 2 are ignored.
The top stack device, after waking up, waits for some time before
sending an ACK response to the master. This wait time is
necessary to allow receipt of the Wake-up signal being originated
by a stack device other than the master. See “Fault Response in
Sleep Mode” on page 76 for more information.
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FN8830.1
June 16, 2016