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DETAILED DESCRIPTION

CONTROL PIN EN: Enable

SINGLE-PIN INTERFACE CONTROL COMMANDS

T0130-01

VDD

EnterProgramming

SequenceandWrite

Word0(TrimPPM)

EN/SDATA

Apply Application

VDDandVerify

Settings(Measure)

Perform

StateJump

Into

Program

EEPROM

HoldforMinimum

10msto Achieve

SafeProgramming

JumpFrom

State3

State1

®

BackIntoNormal

Application After

200- sLow

m

2.25V

VDD

3.3V

£

£

3.1V

VDD

3.3V

£

£

3.1V

VDD

3.3V

£

£

2.25V

VDD

3.3V

£

£

CDCE401

SCAS820 – JUNE 2006

The functions of the EN control pin are listed and explained in Table 2.

Table 2. EN Control Pin Functions

EN

FUNCTION

0

Disabled: all current sources are switched off, output is in the high-impedance state.

1

Enabled: output follows the XIN/XOUT oscillation.

The CDCE401 can be configured and programmed via the SDATA input pin. For this purpose, a

pulse-code-shaped signal must be applied to the device as shown in the waveforms of Figure 1 to select one of

the operation modes described in the State Flow-Diagram of the Single-Pin Interface section. During the

EEPROM programming phase, the device requires a stable VDD of 3.2 V ±100 mV for secure writing of the

EEPROM cells. After each Write-to-WordX, the written data is latched, made effective, and offers look-ahead

before the actual data is stored into the EEPROM.

Table 3 summarizes all valid programming commands.

Figure 1. Typical Programming Cycle

Table 3. Single-Pin Interface Control Commands

SDATA

FUNCTION

00 1100

Enter register programming mode (state 1

→ state 2); bits must be sent in the specified order with the specified

timing. Otherwise, a time-out occurs.

11 1011

Enter register read-back mode; bits must be sent in the specified order with the specified timing. Otherwise a

time-out occurs.

00 xxxx xxxx

10 xxxx xxxx

01 xxxx xxxx

11 xxxx xxxx

State-machine jump: All other patterns not defined as follows cause exit to normal mode.

11 1111 1111

Jump: Exit write-to-RAM (state 2

→ state 1)

11 1111 0000

Jump: Enter EEPROM programming without an EEPROM lock (state 2

→ state 3)

11 0101 0101

Jump: Enter EEPROM programming with EEPROM lock (state 2

→ state 4)

11 0000 0000

Jump: Exit EEPROM programming (state 3 or state 4

→ state 1)

(1)

Each rising edge causes a bit to be latched.

(2)

Between the bits, some longer time delays can occur, but this has no effect on the data.

(3)

look-ahead function.

4

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