Rainbow Electronics DS2422 - Manual (Page 11)

DS2422
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MEMORY
The memory map of the DS2422 is shown in Figure 7. 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 8). Pages 18 and 19 provide storage space for calibration data. They can alternatively be
used as extension of the general-purpose memory. The Trim Register Page holds registers that are used to tune
the timing of the serial data interface and to trim the on-chip temperature converter. The "datalog" logging memory
starts at address 1000h (page 128) and extends over 256 pages. The memory pages 20 to 31 and 33 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- and calibration memory can be written at any time. The access type for the
two register pages and the Trim Register Page is register-specific and depends on whether the device is pro-
grammed for a mission. Figures 8A and 8B show
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 all the
register pages and the calibration memory. See section Address Register and Transfer Status for details.
Figure 8A. DS2422 Register Pages Map
ADDR b7 b6 b5 b4 b3 b2 b1 b0 Function Access*
0200h 0 10 Seconds Single Seconds
0201h 0 10 Minutes Single Minutes Real-
0202h 0 12/24
20h.
AM/PM
10h. Single Hours Time Clock R/W; R
0203h 0 0 10 Date Single Date Registers
0204h CENT 0 0 10m. Single Months
0205h 10 Years Single Years
0206h Low Byte Sample
0207h 0 0 High Byte Rate
R/W; R
0208h Low Threshold Temp.
0209h High Threshold Alarms
R/W; R
020Ah Low Threshold
020Bh High Threshold
Data
Alarms
R/W; R
020Ch Low Byte 0 0 0 0 0 Latest R; R
020Dh High Byte Temp.
020Eh Low Byte
020Fh High Byte
Latest
Data
R; R
0210h 0 0 0 0 0 0 ETHA ETLA T.Alm.En. R/W; R
0211h 1 1 1 1 1 1 EDHA EDLA D.Alm.En. R/W; R
0212h 0 0 0 0 0 0 EHSS EOSC RTC En. R/W; R
0213h 1 1 SUTA RO DLFS TLFS EDL ETL Mis. Cntrl. R/W; R
0214h BOR 1 1 1 DHF DLF THF TLF Alm. Stat. R; R
0215h 1 1 0 WFTA MEMC
LR
0 MIP 0 Gen. Stat. R; R
0216h Low Byte Start
0217h Center Byte Delay R/W; R
0218h High Byte Counter
0219h 0 10 Seconds Single Seconds
021Ah 0 10 Minutes Single Minutes
021Bh 0 12/24
20h.
AM/PM
10h. Single Hours
Mission
Time
R; R
021Ch 0 0 10 Date Single Date Stamp
021Dh CENT 0 0 10m. Single Months
021Eh 10 Years Single Years
021Fh (no function; reads 00h) (N/A) R; R
0220h Low Byte Mission
0221h Center Byte Samples R; R
0222h High Byte Counter
0223h Low Byte Device
0224h Center Byte Samples R; R
0225h High Byte Counter
0226h Configuration Code Flavor R; R
0227h EPW PW. Cntrl. R/W; R