MAX1660 Datasheet, PDF (14/20 Pages) Maxim Integrated Products – Digitally Controlled Fuel-Gauge Interface

Digitally Controlled
Fuel-Gauge Interface
low byte of 0xA (ODHI = OCHI = 1, ODLO = OCLO
= 0) to force the FETs off and disconnect the load. The
MAX1660 does not perform a power-on reset when
exiting soft-shutdown mode.
SMBus Interface
The MAX1660’s 2-wire serial interface is compatible
with Intel’s SMBus interface. An interrupt output (INT)
allows the MAX1660 to immediately interrupt its host in
the event of an overcurrent condition. This interrupt
complies with the SMBALERT# signal of the SMBus
specification. Although each of the MAX1660’s pins are
designed to protect against ±2kV ESD strikes, SDA and
SCL pins have extended ESD-protection structures
designed to provide protection for ±4kV ESD.
The MAX1660 operates as an SMBus slave only, never
as a master. It does not initiate communication on the
bus; it only receives commands and responds to
queries for status information. Although the MAX1660
offers the host an array of configuration commands,
providing complete control over many of its functions, it
performs its functions automatically. The host needs to
communicate with the MAX1660 only to retrieve data
and change configurations as necessary.
Each communication with the MAX1660 begins with a
start condition, defined as a falling edge on SDA with
SCL high. The device address follows the start condi-
tion. The MAX1660 device address is fixed at
0b1000111 (where 0b indicates a binary number),
which may also be denoted as 0x8E (where 0x indi-
cates a hexadecimal number) for Read-Word com-
mands, or 0x8F for Write-Word commands. Figure 9
shows examples of SMBus Write-Word and Read-Word
protocols.
ReadStatus() Command
The host determines the MAX1660’s status by execut-
ing the ReadStatus() command. This command returns
the MAX1660’s status, including the state of its inter-
rupts, as well as the present direction of current flow.
Table 5 describes each of the status word’s bits.
Status information is retrieved from the MAX1660 using
the Read-Word protocol; however, the device’s flexible
implementation of the SMBus standard also allows the
Receive-Byte protocol to be substituted when status is
being read. When the MAX1660 receives a command,
its command code is latched, remaining valid until it is
overwritten by a new command code. When status
information is repeatedly being read, polling time can
be significantly decreased by using the Receive-Byte
protocol to read the status word’s LSB after the initial
ReadStatus() command.
STOP
ACK
D8
D9
D10
D11
D12
D13
D14
D15
ACK
D0
D1
D2
D3
D4
D5
D6
D7
ACK
CMD0
CMD1
CMD2
CMD3
CMD4
CMD5
CMD6
CMD7
ACK
W
1
1
1
0
0
0
1
STOP
ACK
D8
D9
D10
D11
D12
D13
D14
D15
ACK
D0
D1
D2
D3
D4
D5
D6
D7
ACK
R
1
1
1
0
0
0
1
REPEATED
START
ACK
CMD0
CMD1
CMD2
CMD3
CMD4
CMD5
CMD6
CMD7
ACK
W
1
1
1
0
0
0
1
START
START
Figure 9. Write-Word and Read-Word Examples
*Patent pending
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