Datasheet LTC2984 (Analog Devices) - 23
| Manufacturer | Analog Devices |
| Description | Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM |
| Pages / Page | 78 / 23 — APPLICATIONS INFORMATION EEPROM OVERVIEW. EEPROM WRITE OPERATION. Figure … |
| File Format / Size | PDF / 835 Kb |
| Document Language | English |
APPLICATIONS INFORMATION EEPROM OVERVIEW. EEPROM WRITE OPERATION. Figure 5. Sensor-Configuration. Set EEPROM Key
Model Line for this Datasheet
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LTC2984
APPLICATIONS INFORMATION EEPROM OVERVIEW EEPROM WRITE OPERATION
The LTC2984 contains 512 bytes of EEPROM, which The EEPROM write operation requires 5 steps (see Figure 5). shadows the upper sensor configuration segment of USER LTC2984 RAM (locations 0x200–0x3CF, see Figure 4). Prior to initial READY usage, the user programs the USER RAM with all channel WRITE CHANNEL ASSIGNMENT assignment and custom sensor data. Once the USER RAM AND CUSTOM SENSOR DATA TO LTC2984 has been programmed, the user can save this segment of memory into the EEPROM. After subsequent power down WRITE EEPROM KEY or sleep cycles, the user can reload the USER RAM with this TO LTC2984 stored EEPROM data bypassing the channel assignment SEND EEPROM WRITE COMMAND and customer sensor programming normally required. (COMMAND 21) WAIT FOR EEPROM BYTE LTC2984 SPI COMMAND TO COMPLETE ADDRESS ADDRESS SPACE 0000 PROGRAM FAILED CHECK EEPROM STATUS BIT SET USER DEFINED STATUS REGISTER EEPROM USER COMMAND ERROR HANDLER REGISTERS, RESULTS DATA, ELSE GLOBAL CONFIGURATION AND STATUS DONE 2984 F05
Figure 5.
01FF 0200 1.
Sensor-Configuration.
Write all desired channel assignment SENSOR CONFIGURATION MEMORY SEGMENT COMMAND 21 and custom sensor data to the LTC2984 USER RAM. (0x15) (CHANNEL ASSIGNMENT EEPROM 2.
Set EEPROM Key.
Write the EEPROM Key (0xA53C0F5A) AND COMMAND 22 SHADOW CUSTOM SENSOR DATA) (0x16) to the key register space of the LTC2984 USER RAM 03CF (Address range 0x0B0–0x0B3, see Tables 5, 7 and 11). 03DO RESERVED* RESERVED 03FF Note the key is written MSB first. 2984 F04 *NOTE: 03D0–03FF IS RESERVED 3.
Send EEPROM Write Command.
Write the EEPROM write AND IS NOT SHADOWED BY EEPROM
Figure 4. Shadow EEPROM Memory Map
command (0x15) and start bit (0x80) to the LTC2984 command register (Address 0x000). The command plus
EEPROM READ/WRITE VALIDATION
start bit is 0x80 + 0x15 = 0x95 (see Table 12). Access to the EEPROM is key-protected to prevent inad- 4.
Wait for EEPROM Command to Complete.
Completion vertent access. The EEPROM also has two levels of data of the write operation is indicated by both the interrupt integrity protection. The first level is implemented using pin going HIGH and the status register START bit going an error correcting code (ECC) on each 32-bit word of LOW and DONE bit going HIGH. data in the EEPROM. The ECC is capable of correcting 5.
Check EEPROM Status Register.
Read EEPROM Status any single bit error per word and detecting 2-bit errors register (Address 0x0F9) and checks the Program-Failed per word. The second level of protection is implemented status bit (Bit 2) to determine whether the EEPROM write using a 32-bit checksum, which covers the entire contents operation was successful (see Table 13). The Program-Failed of user EEPROM. Status bits are available to the user for status bit being set indicates that the write operation failed. reporting ECC status and checksum error conditions. Upon successful completion of steps 1–5, the EEPROM will now contain the image that was present in USER RAM locations 0x200–0x3CF. 2984fb For more information www.linear.com/LTC2984 23 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Complete System Electrical Characteristics ADC Electrical Characteristics Reference Electrical Characteristics Digital Inputs and Digital Outputs EEPROM Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuits Timing Diagram Overview Applications Information EEPROM Overview Eeprom Read/Write Validation EEPROM Write Operation EEPROM Read Operation Thermocouple Measurements Diode Measurements RTD Measurements Thermistor Measurements Supplemental Information Direct ADC Measurements Fault Protection and Anti-Aliasing 2- and 3-Cycle Conversion Modes Running Conversions Consecutively on Multiple Channels Entering/Exiting Sleep Mode MUX Configuration Delay Global Configuration Register Reference Considerations Custom Thermocouples Custom RTDs Custom Thermistors Package Description Revision History Typical Application Related Parts
APPLICATIONS INFORMATION EEPROM OVERVIEW EEPROM WRITE OPERATION
The LTC2984 contains 512 bytes of EEPROM, which The EEPROM write operation requires 5 steps (see Figure 5). shadows the upper sensor configuration segment of USER LTC2984 RAM (locations 0x200–0x3CF, see Figure 4). Prior to initial READY usage, the user programs the USER RAM with all channel WRITE CHANNEL ASSIGNMENT assignment and custom sensor data. Once the USER RAM AND CUSTOM SENSOR DATA TO LTC2984 has been programmed, the user can save this segment of memory into the EEPROM. After subsequent power down WRITE EEPROM KEY or sleep cycles, the user can reload the USER RAM with this TO LTC2984 stored EEPROM data bypassing the channel assignment SEND EEPROM WRITE COMMAND and customer sensor programming normally required. (COMMAND 21) WAIT FOR EEPROM BYTE LTC2984 SPI COMMAND TO COMPLETE ADDRESS ADDRESS SPACE 0000 PROGRAM FAILED CHECK EEPROM STATUS BIT SET USER DEFINED STATUS REGISTER EEPROM USER COMMAND ERROR HANDLER REGISTERS, RESULTS DATA, ELSE GLOBAL CONFIGURATION AND STATUS DONE 2984 F05
Figure 5.
01FF 0200 1.
Sensor-Configuration.
Write all desired channel assignment SENSOR CONFIGURATION MEMORY SEGMENT COMMAND 21 and custom sensor data to the LTC2984 USER RAM. (0x15) (CHANNEL ASSIGNMENT EEPROM 2.
Set EEPROM Key.
Write the EEPROM Key (0xA53C0F5A) AND COMMAND 22 SHADOW CUSTOM SENSOR DATA) (0x16) to the key register space of the LTC2984 USER RAM 03CF (Address range 0x0B0–0x0B3, see Tables 5, 7 and 11). 03DO RESERVED* RESERVED 03FF Note the key is written MSB first. 2984 F04 *NOTE: 03D0–03FF IS RESERVED 3.
Send EEPROM Write Command.
Write the EEPROM write AND IS NOT SHADOWED BY EEPROM
Figure 4. Shadow EEPROM Memory Map
command (0x15) and start bit (0x80) to the LTC2984 command register (Address 0x000). The command plus
EEPROM READ/WRITE VALIDATION
start bit is 0x80 + 0x15 = 0x95 (see Table 12). Access to the EEPROM is key-protected to prevent inad- 4.
Wait for EEPROM Command to Complete.
Completion vertent access. The EEPROM also has two levels of data of the write operation is indicated by both the interrupt integrity protection. The first level is implemented using pin going HIGH and the status register START bit going an error correcting code (ECC) on each 32-bit word of LOW and DONE bit going HIGH. data in the EEPROM. The ECC is capable of correcting 5.
Check EEPROM Status Register.
Read EEPROM Status any single bit error per word and detecting 2-bit errors register (Address 0x0F9) and checks the Program-Failed per word. The second level of protection is implemented status bit (Bit 2) to determine whether the EEPROM write using a 32-bit checksum, which covers the entire contents operation was successful (see Table 13). The Program-Failed of user EEPROM. Status bits are available to the user for status bit being set indicates that the write operation failed. reporting ECC status and checksum error conditions. Upon successful completion of steps 1–5, the EEPROM will now contain the image that was present in USER RAM locations 0x200–0x3CF. 2984fb For more information www.linear.com/LTC2984 23 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Complete System Electrical Characteristics ADC Electrical Characteristics Reference Electrical Characteristics Digital Inputs and Digital Outputs EEPROM Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuits Timing Diagram Overview Applications Information EEPROM Overview Eeprom Read/Write Validation EEPROM Write Operation EEPROM Read Operation Thermocouple Measurements Diode Measurements RTD Measurements Thermistor Measurements Supplemental Information Direct ADC Measurements Fault Protection and Anti-Aliasing 2- and 3-Cycle Conversion Modes Running Conversions Consecutively on Multiple Channels Entering/Exiting Sleep Mode MUX Configuration Delay Global Configuration Register Reference Considerations Custom Thermocouples Custom RTDs Custom Thermistors Package Description Revision History Typical Application Related Parts