DS2438Z View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated
Part Name
Description
Manufacturer
DS2438Z Datasheet PDF : 29 Pages
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DS2438
Recall Memory [B8hxxh]
This command recalls the stored values in EEPROM / SRAM page xxh to the scratchpad page xxh. This
command must proceed a Read SPxx command in order to read any page of memory on the DS2438.
Valid page numbers are 00h - 07h.
Convert T [44h]
This command begins a temperature conversion. No further data is required. The temperature conversion
will be performed, setting the TB flag in the Status/Configuration register to a “1” during conversion.
When the temperature conversion is done, the TB flag will clear to a “0”. If the bus master issues read
time slots following this command, the DS2438 will output “0” on the bus as long as it is busy making a
temperature conversion; it will return a “1” when the temperature conversion is complete.
Convert V [B4h]
This command instructs the DS2438 to initiate a voltage analog-to-digital conversion cycle. This sets the
ADB flag (see Status/Configuration register discussion in the Memory Map section). The voltage supply
that is measured is defined by the AD bit of the Status/Configuration register. When the A/D conversion
is done, the ADB flag is cleared and the current voltage value is placed in the VOLTAGE REGISTER of
page 00h. While an A/D conversion is taking place, all other memory functions are still available for use.
If the bus master issues read time slots following this command, the DS2438 will output “0” on the bus as
long as it is busy making a voltage measurement; it will return a “1” when the conversion is complete.
DS2438 COMMAND SET Table 11
INSTRUCTION DESCRIPTION
PROTOCOL
1-WIRE BUS
MASTER STATUS
AFTER ISSUING
PROTOCOL
MEMORY COMMANDS
Read Scratchpad
Reads bytes from
BEh <page
Rx
DS2438 Scratchpad
00h-07h>
page xxh
Write Scratchpad
Writes bytes to
4Eh <page
Tx
DS2438
00h-07h>
Scratchpad page xxh
1-WIRE BUS
DATA AFTER
ISSUING
PROTOCOL
<read up to nine
bytes of data>
<write up to eight
bytes of data>
Copy Scratchpad
Recall Memory
Convert T
Convert V
Copies entire contents
of Scratchpad page
xxh
to 8-byte EEPROM/
48h<page
00h-07h>
Idle or Rx of NVB bit
SRAM page xxh
Copies entire contents
B8h<page
Idle
of EEPROM/SRAM
00h-07h>
page xxh to
Scratchpad
page xxh
REGISTER COMMANDS
Initiates temperature
44h
Idle or Rx of TB bit
conversion
Initiates voltage A/D
conversion
B4h
Idle or Rx of ADB bit
{NVB bit in Status
Register = 1 until
copy complete (2-
10 ms, typ)}
Idle
{TB bit in Status
Register = 1 until
conversion
complete}
{ADB bit in Status
Register = 1 until
conversion
complete}
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