1. Initiate a one-shot conversion using Command

Byte 0Fh. When this conversion is complete, read

the contents of the Temperature Data registers.

2) If the MAX6657/MAX6658/MAX6659 are in run mode,

read the Status register. If a conversion is in

progress, the BUSY bit is set to 1. Wait for the con-

version to complete as indicated by the BUSY bit

being set to 0, then read the Temperature Data reg-

isters. Note that the power-on reset sets the conver-

sion rate to 16Hz, so no extended data is valid

without reducing the conversion rate to 4Hz or less.

Diode Fault Alarm

There is a continuity fault detector at DXP that detects

an open circuit between DXP and DXN, or a DXP short

the external temperature register is loaded with 1000

0000. Additionally, if the fault is an open circuit, bit 2

(OPEN) of the status byte is set to 1 and the ALERT con-

dition is activated at the end of the conversion.

Immediately after POR, the Status register indicates that

no fault is present until the end of the first conversion.

10

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SMBCLK

AB

C

D

E

FG

H

I

J

K

SMBDATA

L

M

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

E = SLAVE PULLS SMBDATA LINE LOW

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO MASTER

H = LSB OF DATA CLOCKED INTO MASTER

I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION

M = NEW START CONDITION

Figure 4. SMBus Read Timing Diagram

SMBCLK

AB

C

D

E

FG

H

I

J

K

SMBDATA

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

E = SLAVE PULLS SMBDATA LINE LOW

L

M

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO SLAVE

H = LSB OF DATA CLOCKED INTO SLAVE

I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION

M = NEW START CONDITION

Figure 3. SMBus Write Timing Diagram

±1°C, SMBus-Compatible Remote/Local Temperature

Sensors with Overtemperature Alarms