Rainbow Electronics MAX6649 - Manual (Page 10)

MAX6649
+145°C Precision SMBus-Compatible Remote/
Local Sensor with Overtemperature Alarms
10 ______________________________________________________________________________________
Valid A/D conversion results for both channels are avail-
able one total conversion time (125ms nominal, 156ms
maximum) after initiating a conversion, whether conver-
sion is initiated through the RUN bit, one-shot com-
mand, or initial power-up. Changing the conversion rate
can also affect the delay until new results are available.
Slave Addresses
The MAX6649 has a fixed address of 1001 100. The
MAX6649 also responds to the SMBus alert response
slave address (see the Alert Response Address section).
POR and UVLO
To prevent ambiguous power-supply conditions from
corrupting the data in memory and causing erratic
behavior, a POR voltage detector monitors V
CC and
clears the memory if V CC falls below 2.0V (typ). When
power is first applied and V CC rises above 2.0V (typ),
the logic blocks begin operating, although reads and
REGISTER ADDRESS POR STATE FUNCTION
RLTS 00h 0000 0000 0°C Read local (internal) temperature
RRTE 01h 0000 0000 0°C Read remote (external) temperature
RSL 02h N/A — Read status byte
RCL 03h 0000 0000 — Read configuration byte
RCRA 04h 0000 0111 — Read conversion rate byte
RLHN 05h 0101 0101 +85°C Read local (internal) ALERT high limit
RLLI 06h 0000 0000 0°C Read local (internal) ALERT low limit
RRHI 07h 0101 0101 +85°C Read remote (external) ALERT high limit
RRLS 08h 0000 0000 0°C Read remote (external) ALERT low limit
WCA 09h N/A — Write configuration byte
WCRW 0Ah N/A — Write conversion rate byte
WLHO 0Bh N/A — Write local (internal) ALERT high limit
WLLM 0Ch N/A — Write local (internal) ALERT low limit
WRHA 0Dh N/A — Write remote (external) ALERT high limit
WRLN 0Eh N/A — Write remote (external) ALERT low limit
OSHT 0Fh N/A — One-shot
REET 10h 0000 0000 0°C Read remote (external) extended temperature
RIET 11h 0000 0000 0°C Read local (internal) extended temperature
RWOE 19h 0101 0101 +85°C Read/write remote (external) OVERT limit (MAX6649)
RWOI 20h 0101 0101 +85°C Read/write local (internal) OVERT limit
HYS 21h 0000 1010 10°C Overtemperature hysteresis
QUEUE 22h 1000 0110 — Fault queue
— FEh 0100 1101 — Read manufacture ID
— FFh 0101 1001 — Read revision ID
Table 5. Command-Byte Bit Assignments
BIT NAME POR STATE FUNCTION
7 (MSB) MASK 0 Masks ALERT interrupts when set to 1.
6 RUN 0 Standby mode control bit; if set to 1, standby mode is initiated.
5 to 0 RFU 0 Reserved.
Table 6. Configuration-Byte Bit Assignments (03h)