JAJSD83C May 2017 – October 2019 TMP464
PRODUCTION DATA.
All of the configuration and limit registers may be locked for writes (making the registers write-protected), which decreases the chance of software runaway from issuing false changes to these registers. The Lock column in Table 3 identifies which registers may be locked. Lock mode does not effect read operations. To activate the lock mode, Lock Register C4h must be set to 0x5CA6. The lock only remains active while the TMP464 device is powered up. Because the TMP464 device does not contain nonvolatile memory, the settings of the configuration and limit registers are lost once a power cycle occurs regardless if the registers are locked or unlocked.
In lock mode, the TMP464 device ignores a write operation to configuration and limit registers except for Lock Register C4h. The TMP464 device does not acknowledge the data bytes during a write operation to a locked register. To unlock the TMP464 registers, write 0xEB19 to register C4h. The TMP464 device powers up in locked mode, so the registers must be unlocked before the registers accept writes of new data.