MAX1660EEE(1998) Просмотр технического описания (PDF) - Maxim Integrated

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MAX1660EEE
(Rev.:1998)

Digitally Controlled Fuel-Gauge Interface

Maxim Integrated 

Digitally Controlled

Fuel-Gauge Interface

Use the WriteComp01 and WriteComp23 commands to

define the COMP register contents (Table 3). Since the

Write-Word protocol supports only 16-bit data transfers,

sequentially execute these commands to write the

entire 32-bit COMP word. First execute WriteComp01

to write COMP0 and COMP1, and then execute

WriteComp23 to write COMP2 and COMP3. Executing

WriteComp01 internally disables the COMPINT interrupt

and writes the Write-Word protocol’s LSB into COMP0

and its MSB into COMP1. The COMPINT interrupt dis-

ables on SCL’s 18th rising edge during WriteComp01

execution (Figure 6). Executing WriteComp23 writes the

Write-Word protocol’s LSB and MSB into COMP2 and

COMP3, and enables the COMPINT interrupt. The

COMPINT interrupt reenables on the falling edge fol-

lowing SCL’s 36th rising edge during WriteComp23

execution. Disabling the COMPINT interrupt with the

WriteComp01 command prevents an erroneous inter-

rupt, due to incomplete data in the COMP register. To

ensure proper execution, issue these commands in the

correct sequence.

Direction-Change Detection Function

The MAX1660’s direction-change detection function

informs the host whenever the current flow changes

direction. When it is used in conjunction with the

MAX1660’s digital compare function and CHARGE-

STATUS bit in end-of-charge and end-of-discharge

detection routines, the host can ensure that the digital

compare function continues to monitor the proper

counter when the current flow changes direction.

The direction-change function is simple: the status

word’s DIRCHANGE bit sets any time the current flow

changes direction. Once DIRCHANGE is set, it remains

set until it is cleared; additional changes in the current-

flow direction do not affect the bit. To clear the DIR-

CHANGE bit, write a 1 to the configuration word’s

CLRINT bit. DIRCHANGE also clears when the

MAX1660 enters soft-shutdown mode and after a

power-on reset. In end-of-charge and end-of-discharge

routines, in which the host must be informed immediate-

ly of a change in current-flow direction, set the configu-

ration word’s DIRINTENABLE bit to generate an interrupt

whenever the status word’s DIRCHANGE bit is set.

Table 3. Write-Word Commands

COMMAND

NAME

WriteComp01

WriteComp23

WriteConfig()

COMMAND

CODE

0x00

0x01

0x04

DESCRIPTION

Disables the COMPINT interrupt; writes the Write-Word protocol’s LSB into COMP0 and its MSB into

COMP1.

Writes the Write-Word protocol’s LSB into COMP2 and its MSB into COMP3, and enables the

COMPINT interrupt.

Writes the Write-Word protocol’s data bytes into the configuration word. See Table 6 for a descrip-

tion of the configuration bits.

18TH RISING EDGE OF

SCL DURING WriteComp01

WRITE-WORD PROTOCOL

ACK BIT CLOCKED

INTO HOST

STOP

CONDITION

SCL

36TH RISING EDGE OF

SCL DURING WriteComp23

WRITE-WORD PROTOCOL

ACK BIT CLOCKED

INTO HOST

STOP

CONDITION

INTERRUPT

DISABLES ON

SCL’s RISING

EDGE

SDA

INTERRUPT

ENABLES ON

SCL’s FALLING

EDGE

BOLD LINE INDICATES MAX1660

PULLING SDA LOW

Figure 6. Automatic Interrupt Enable/Disable During COMP Update

*Patent pending

10 ______________________________________________________________________________________

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