DS2251T View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
DS2251T Datasheet PDF : 22 Pages
| |||
DS2251T MEMORY MAP WITH (PES = 1) Figure 4
DS2251T
POWER MANAGEMENT
The DS2251T monitors VCC to provide power-fail reset, early warning power-fail interrupt, and
switchover to lithium backup. It uses an internal band-gap reference in determining the switch points.
These are called VPFW, VCCMIN, and VLI, respectively. When VCC drops below VPFW, the DS2251T will
perform an interrupt vector to location 2Bh if the power-fail warning is enabled. Full processor operation
continues regardless. When power falls further to VCCMIN, the DS2251T invokes a reset state. No further
code execution will be performed unless power rises back above VCCMIN. All decoded chip enables and
the R/ W signal go to an inactive (logic 1) state. The VRST signal will be driven to a logic 0. VCC is still
the power source at this time. When VCC drops further to below VLI, internal circuitry will switch to the
built-in lithium cell for power. The majority of internal circuits will be disabled and the remaining
nonvolatile states will be retained. PF will be driven to a logic 0. The Secure Microcontroller User’s
Guide has more information on this topic. The trip points VCCMIN and VPFW are listed in the electrical
specifications.
8 of 22
Share Link: 