MAX1458 Datasheet, PDF (11/20 Pages) Maxim Integrated Products – 1%-Accurate, Digitally Trimmed Sensor Signal Conditioner

1%-Accurate, Digitally Trimmed
Sensor Signal Conditioner
high. In addition, the EEPROM should only be written to
at T_A = +25°C and V_DD = 5V.
Writing to the internal EEPROM is a time-consuming
process and should only be required once. All calibra-
tion/compensation coefficients are determined by writ-
ing directly to the DAC and configuration registers. Use
the following procedure to write these calibration/com-
pensation coefficients to the EEPROM:
1) Issue an ERASE EEPROM command.
2) Wait 50ms (t_WRITE).
3) Issue on END EEPROM WRITE command at
address 00h.
4) Wait 1ms (t_WAIT).
5) Issue a BEGIN EEPROM WRITE command
(Figure 7) at the address of the bit to be set.
6) Wait 50ms.
7) Issue an END EEPROM WRITE command (Figure 7)
using the same address as in Step 5.
8) Wait 1ms.
9) Return to Step 5 until all necessary bits have been
set.
10) Read EEPROM to verify that the correct calibra-
tion/compensation coefficients have been stored.
READ EEPROM Command
The READ EEPROM command returns the bit stored at
the memory location addressed by the lower seven bits
of the data field (A0–A6). The higher bits of the data
field (A7–A11) are ignored. Note that after a read com-
mand has been issued, the DIO lines become an out-
put and the state of the addressed EEPROM location
will be available on DIO 200µs (t_READ) after the falling
edge of the 16th SCLK cycle (Figure 8). After issuing
the READ EEPROM command, DIO returns to input
mode on the falling edge of CS. Reading the entire
EEPROM requires the READ EEPROM command be
issued 128 times.
SCLK
DIO
SCLK
DATA
COMMAND
LSB
MSB LSB
MSB
A0 A1 A2 A3 A4 A5 A6 0 0 0 0 0 0 1 0 0
16-BIT COMMAND WORD – BEGIN EEPROM WRITE AT ADDRESS COMMAND
LSB
MSB
DATA
COMMAND
LSB
MSB LSB
MSB
DIO A0 A1 A2 A3 A4 A5 A6 0 0 0 0 0 1 0 1 0
16-BIT COMMAND WORD – END EEPROM WRITE AT ADDRESS COMMAND
LSB
MSB
Figure 7. Begin WRITE EEPROM and End WRITE EEPROM Timing Diagrams
CS
t_MIN = 200µs
16 CLOCK CYCLES
SCLK
t_READ
DIO
X
1 0 1 0 U 0 A0 A1 A2 A3 A4 A5 A6 0 0 0 0 0 1 1 0 0 X EE DATA
X
INIT SEQUENCE
READ EEPROM AT ADDRESS COMMAND
DIO IS AN INPUT PIN
DIO IS AN
OUTPUT PIN
Figure 8. READ EEPROM Timing Diagram
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