DS1680

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CEO pins. The backup energy source used to power the RTC is also used to retain RAM data in the

transients to prevent data corruption.

The DS1680’s microprocessor- monitor circuitry provides three basic functions. First, a precision

tolerance condition occurs, an internal power-fail signal is generated that forces

RST to the active state.

the power supply and processor to stabilize. The DS1680 debounces a pus hbutton input and guarantees an

The DS1680 also provides a touch-screen controller along with a 10-bit successive approximation ADC.

The ADC is monotonic (no missing codes) and has an internal analog filter to reduce high frequency

noise.

DS1680 BLOCK DIAGRAM Figure 1

CLOCK

OSC

CLOCK

GEN

PANEL

DRIVE

CONVERT

CONTROL

10-BIT

ADC

INPUT

MUX

TOUCH

DETECT

POWER

CONTROL

RTC

SERIAL

INTERFACE

WATCHDOG

OUTPUT

MUX

BHE

OUT_SELECT

PEN_SELECT

AIN0

AIN1

COEN

CONVERT

PEN_OFF

PD_RST

D0-D7

OSCIN

X1

X2

INT

SCLK

CS

I/O

ST

RST

POWER SWITCH,

WRITE PROTECT,

NV CONTROL,

AND

POWER FAIL

WARNING

CEI

CEO

PFI

PFO

ANSELIN

X+

X-

Y+

Y-

NEW_DATA