DS2436 Dallas Semiconducotr, DS2436 Datasheet - Page 10

• Manufacturer Part Number: DS2436
• Description: Battery ID/Monitor Chip
• Manufacturer: Dallas Semiconducotr

DS2436
MEMORY
The DS2436’s memory is divided into five pages, each page filling 32 bytes of address space. Not all of
the available addresses are used, however. Refer to the memory map of Figure 3 to see actual addresses
which are available.
The first three pages of memory consist of a scratchpad RAM and either EEPROM (pages 1 and 2) or
SRAM (page 3). The scratchpads help insure data integrity when communicating over the 1-Wire bus.
Data is first written to the scratchpad where it can be read back. After the data has been verified, a copy
scratchpad command will transfer the data to the EEPROM or SRAM. This process insures data integrity
when modifying the memory.
The fourth page of memory consists of registers which contain the Temperature, Voltage, and Status
registers. These registers are made from SRAM cells, except for the lock bit in the status register which is
implemented in EEPROM.
The fifth page of memory holds the Manufacturer ID and Cycle Count registers implemented in
EEPROM.
PAGE 1
The first page of memory has 24 bytes. It consists of scratchpad RAM and nonvolatile EEPROM
memory. These 24 bytes may be used to store any data, such as: battery chemistry descriptors,
manufacturing lot codes, etc.
This page may be locked to prevent data stored here from being changed inadvertently.
The nonvolatile and the scratchpad portions of this page are organized identically, as shown in Figure 3.
In this page, these two portions are referred to as NV1 and SP1, respectively.
PAGE 2
The second page of memory has 8 bytes. It consists of a scratchpad RAM and a nonvolatile EEPROM
memory. These 8 bytes may be used to store additional data. In contrast to Page 1 memory, the Lock
function is not available for Page 2.
PAGE 3
The third page of memory has 8 bytes. It consists of a scratchpad RAM and an SRAM memory. This
address space may be used to store additional data, provided that, should the battery discharge completely
and power to the DS2436 is lost, this data may also be lost without serious repercussions. Data which
must remain even if power to the DS2436 is lost should be placed in either Page 1 or Page 2.
Prefer this section of memory to store fuel gauge and self discharge information. If the battery dies and
this information is lost, no serious consequences will result since the user can easily determine that the
battery is dead.
PAGE 4
The fourth page of memory is used by the DS2436 to store the battery temperature and
voltage. A 2-byte Status Register informs of conversion progress and memory lock state.
10 of 29