DS1922T-F5 MAXIM [Maxim Integrated Products], DS1922T-F5 Datasheet - Page 15

• Manufacturer Part Number: DS1922T-F5
• Description: Temperature Logger iButton With 8kB Datalog Memory
• Manufacturer: MAXIM [Maxim Integrated Products]

MEMORY
The memory map of the DS1922L/T is shown in Figure 5. The 512 bytes general-purpose SRAM are located in
pages 0 through 15. The various registers to set-up and control the device fill page 16 and 17, called register pages
1 and 2 (details in Figure 6). Pages 18 and 19 provide storage space for calibration data. They can alternatively be
used as extension of the general-purpose memory. The "datalog" logging memory starts at address 1000h (page
128) and extends over 256 pages. The memory pages 20 to 127 are reserved for future extensions. The
scratchpad is an additional page that acts as a buffer when writing to the SRAM memory or the register page. The
data memory can be written at any time. The calibration memory holds data from the device calibration that can be
used to further improve the accuracy of 11-bit temperature readings. See the Software Correction Algorithm for
Temperature section for details. The last byte of the calibration memory page stores an 8-bit CRC of the
preceeding 31 bytes. Page 19 is an exact copy of the data in page 18. While the calibration memory can be
overwritten by the user, this is not recommended. See section Security by Password for ways to protect the
memory. The access type for the register pages is register-specific and depends on whether the device is pro-
grammed for a mission. Figure 6 shows the details. The datalog memory is read-only for the user. It is written
solely under supervision of the on-chip control logic. Due to the special behavior of the write access logic (write
scratchpad, copy scratchpad) it is recommended to only write full pages at a time. This also applies to the register
pages and the calibration memory. See the Address Register and Transfer Status section for details.
Figure 5. DS1922L/T Memory Map
ADDRESS
0000H to
0020H to
0200H to
0220H to
0240H to
0260H to
0280H to
1000H to
0FFFH
2FFFH
01FFH
001FH
021FH
023FH
025FH
027FH
32-Byte Intermediate Storage Scratchpad
32-Byte General-Purpose SRAM (R/W)
Calibration Memory Page 1 (R/W)
Calibration Memory Page 2 (R/W)
(Reserved For Future Extensions)
General-Purpose SRAM (R/W)
Datalog Memory (Read-Only)
32-Byte Register Page 1
32-Byte Register Page 2
15 of 50
Pages 20 to 127
Pages 128
Pages 1
Page 16
Page 17
Page 18
Page 19
Page 0
to 383
to 15
DS1922L/DS1922T