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Control and operation of a/d conversion, Starting up the a/d converter circuit, Starting a/d conversion – Epson S1C33210 User Manual

Page 437

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IV ANALOG BLOCK: A/D CONVERTER

S1C33210 FUNCTION PART

EPSON

B-IV-2-5

Control and Operation of A/D Conversion

Figure 2.2 shows the operation of the A/D converter.

ADE

Trigger

ADST

A/D operation

ADD

ADF

Conversion-result read

OWE

Interrupt request

AD0

AD0

Sampling

Conversion

AD1

AD1

Sampling

Conversion

AD2

AD0 converted data

AD1 converted data

(When AD0 to AD2 are converted)

AD2 converted data

ADD is overwritten

AD2

Sampling

Conversion

(1) Normal mode

ADE

Trigger

ADST

A/D operation

ADD

ADF

Conversion-result read

OWE

Interrupt request

AD0-1

AD0-1

Sampling

Conversion

AD0-2

AD0-2

Sampling

Conversion

AD0-3

AD0-1 converted data AD0-2 converted data

(When only AD0 is converted)

Reset in software

invalid

Sampling Conversion

(2) Continuous mode

Figure 2.2 Operation of A/D Converter

Starting up the A/D converter circuit

After the settings specified in the preceding section have been made, write "1" to ADE (D2) / A/D enable
register (0x40244) to enable the A/D converter. The A/D converter is thereby readied to accept a trigger to start
A/D conversion. To set the A/D converter again, or if it is not be used, set ADE to "0".

Starting A/D conversion

When a trigger is input while ADE = "1", A/D conversion is started. If a software trigger has been selected,
A/D conversion is started by writing "1" to ADST (D1) / A/D enable register (0x40244).
Only the trigger selected using TS[1:0] (D[4:3]) / A/D trigger register (0x40242) are valid; no other trigger is
accepted.