TMP107

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SBOS716B – MAY 2015 – REVISED SEPTEMBER 2015

7.5 Programming

7.5.1 EEPROM

The TMP107 has an internal EEPROM that is used to program and store values for writable registers, such as

the configuration, high limit, and low limit registers. The EEPROM also has eight, 16-bit locations of general-

purpose memory. By programming the configuration register, the EEPROM is used to store critical, system

information, such as unique calibration information for the host, unique system serial ID, or a user-specific

conversion rate. During the reset event, the data from the EEPROM are copied into the corresponding registers.

Two registers that are not updated by the EEPROM are the temperature register and die identification register.

The electrical and timing specifications for the EEPROM are provided in the Specifications section. See Table 3

for the register map to the eight, internal EEPROM locations (register addresses 6h to Dh).

7.5.2 EEPROM Operations

7.5.2.1 EEPROM Unlock

After power up, the EEPROM is locked for programming by default. When locked, all writes to the EEPROM are

ignored. In order to program the EEPROM, first unlock the memory for programming by writing logic 1 to NUS

(bit 0 in the temperature register) using a regular write communication. EEPROM locations are readable whether

locked or unlocked. Locking the EEPROM by default is a protection provided to prevent unintentional triggering

of EEPROM programming during normal device operations.

7.5.2.2 EEPROM Lock

If the EEPROM is unlocked for programming, make sure to lock the EEPROM after the programming operations.

Lock the EEPROM by writing logic 0 to NUS (bit 0 in the temperature register).

7.5.2.3 EEPROM Programming

After the EEPROM is unlocked, a write to any EEPROM-associated register triggers EEPROM programming. A

programming event takes up to 16 ms, depending on the device conditions; therefore, space out successive

commands in 16-ms write periods.

Poll BUSY (bit 1 in the temperature register) to check the EEPROM programming status. The BUSY bit = 1 when

the EEPROM program is in progress. The BUSY bit = 0 after programming is complete and the EEPROM is

ready for another program operation. While the EEPROM is being programmed, writes to every other register are

prevented in order to protect device data from corruption until programming is complete.

When the global write operation is issued to program the EEPROM locations, all of the devices in the daisy chain

specified within the address field perform the programming simultaneously. This simultaneous programming

leads to an increase in current in the supply wire of the daisy chain, and may create a drop in the supply voltage.

It is important to maintain the supply voltage at greater than 1.8 V during the EEPROM programming in order to

program devices in the daisy chain.

7.5.2.4 EEPROM Acquire or Read

The EEPROM locations that store the power-on reset values of the registers are automatically loaded into the

corresponding registers at reset. The general-purpose EEPROM locations are readable even when the EEPROM

is locked. While a read is performed on an EEPROM location in the register map, there is a slightly longer delay

in the stop bit (~100 µs) between the pointer phase and the phase data in the communication in order to allow

the EEPROM to be read. The standard UART protocol allows for such delays when the UART transceiver is

being used. The amount of current consumption from the EEPROM read is negligible compared to the current

consumption from communication.

Copyright © 2015, Texas Instruments Incorporated

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