ST92185B2 datasheet(154/178 Pages) STMICROELECTRONICS

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ST92185B - A/D CONVERTER (A/D)

A/D CONVERTER (Cont’d)

7.7.4 Register Description

A/D CONTROL LOGIC REGISTER (ADCLR)

R241 - Read/Write

Reset value: 0000 0000 (00h)

This 8-bit register manages the A/D logic opera-

tions. Any write operation to it will cause the cur-

rent conversion to be aborted and the logic to be

re-initialized to the starting configuration.

Bit 7:5 = C[2:0]:

Channel Address.

These bits are set and cleared by software. They

select channel i conversion as follows:

Bit 4 = FS:

Fast/Slow.

This bit is set and cleared by software.

0: Fast mode. Single conversion time: 78 x

INTCLK (5.75µs at INTCLK = 12 MHz)

1: Slow mode. Single conversion time: 138 x

INTCLK (11.5µs at INTCLK = 12 MHz)

Note: Fast conversion mode is only allowed for in-

ternal speeds which do not exceed 12 MHz.

Bit 3 = TRG:

External/Internal Trigger Enable.

This bit is set and cleared by software.

0: External/Internal Trigger disabled.

1: Either a negative (falling) edge on the EXTRG

pin or an On Chip Event writes a “1” into the

STR bit, enabling start of conversion.

Note: Triggering by on chip event is available on

devices with the multifunction timer (MFT) periph-

eral.

Bit 2 = POW:

Power Enable.

This bit is set and cleared by software.

0: Disables all power consuming logic.

1: Enables the A/D logic and analog circuitry.

Bit 1 = CONT:

Continuous/Single Mode Select.

This bit it set and cleared by software.

0: Single mode: after the current conversion ends,

the STR bit is reset by hardware and the con-

verter logic is put in a wait status. To start anoth-

er conversion, the STR bit has to be set by soft-

ware or hardware.

1: Select Continuous Mode, a continuous flow of

A/D conversions on the selected channel, start-

ing when the STR bit is set.

Bit 0 = STR:

Start/Stop.

This bit is set and cleared by software. It is also set

by hardware when the A/D is synchronized with an

external/internal trigger.

0: Stop conversion on channel i. An interrupt is

generated if the STR was previously set and the

AD-INT bit is set.

1: Start conversion on channel i

WARNING: When accessing this register, it is rec-

ommended to keep the related A/D interrupt chan-

nel masked or disabled to avoid spurious interrupt

requests.

TRG POW CONT STR

Channel Enabled

Channel 0

Channel 1

Channel 2

Channel 4

Channel 3

ST92185B2 Datasheet(PDF) 154 Page - STMicroelectronics

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