Datasheet

DS620 Digital Thermometer and Thermostat
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PO PIN
The PO pin is a user-programmable open-drain output, which is configured through the PO1 and PO2 bits in the
configuration register. PO can operate as a thermostat output (PO
-HIGH
or PO
-LOW
), or it can be forced low for control
of peripheral devices. When PO is configured as PO
-HIGH
or PO
-LOW
, this pin operates as described in the
Thermostat Operation section. This pin can be reconfigured at anytime to switch between functions. Table 3
defines the various configuration options for this pin.
Table 3. PO Configuration
Function PO2 PO1
Thermostat Output (PO-high) 1 1
Thermostat Output (PO-low) 1 0
Force PO Low 0 X
EEPROM REGISTERS AND MEMORY MAP
The DS620 has a 14-byte linear address space with registers for temperature, thermostat thresholds, and control
as well as four bytes of user EEPROM for general use. All address space is shadowed by RAM. The DS620
Memory Map is shown in Table 4.
See the Writing to the DS620 and the Reading from the DS620 sections for details in writing to and reading from
the DS620 EEPROM registers and memory map.
Table 4. Memory Map
Address (hex) Description
A0 TH MSB
A1 TH LSB
A2 TL MSB
A3 TL LSB
A4 User
A5 User
A6 User
A7 User
A8 Undefined
A9 Undefined
AA Temperature MSB
AB Temperature LSB
AC Configuration MSB
AD Configuration LSB
CONFIGURATION REGISTER
The configuration register allows the user to program various DS620 options such as conversion resolution,
operating mode, and thermostat capability. It also provides information to the user about conversion status,
EEPROM activity, device address, and thermostat activity. The configuration register is arranged as shown in
Figure 5 and detailed descriptions of each bit are provided in Table 5. It is located in address spaces ACh (MSB)
and ADh (LSB) in the DS620 memory. Note that the R0, R1, AUTOC, 1SHOT, and PO1 bits are stored in
EEPROM so they can be programmed prior to installation if desired. All other configuration bits are SRAM and
power up in the state shown in Table 5.