Datasheet
0,ValueDigital =
V0inputwhen £
VV
V
VoltageAnalogInput
4096ValueDigital
REFLOREFHI
REFLO
-
-
´=
V
inputV0when
REFHI
<<
4095,ValueDigital =
V
inputwhen
REFHI
³
0,ValueDigital =
V0inputwhen £
3.3
V
VoltageAnalogInput
4096ValueDigital
REFLO
-
´=
V3.3inputV0when <<
4095,ValueDigital =
V3.3inputwhen ³
TMS320F28027, TMS320F28026, TMS320F28023, TMS320F28022
TMS320F28021, TMS320F28020, TMS320F280200
www.ti.com
SPRS523J –NOVEMBER 2008–REVISED OCTOBER 2013
4.1.1 ADC
4.1.1.1 Features
The core of the ADC contains a single 12-bit converter fed by two sample-and-hold circuits. The sample-
and-hold circuits can be sampled simultaneously or sequentially. These, in turn, are fed by a total of up to
13 analog input channels. The converter can be configured to run with an internal bandgap reference to
create true-voltage based conversions or with a pair of external voltage references (V
REFHI
/V
REFLO
) to
create ratiometric-based conversions.
Contrary to previous ADC types, this ADC is not sequencer-based. It is easy for the user to create a
series of conversions from a single trigger. However, the basic principle of operation is centered around
the configurations of individual conversions, called SOCs, or Start-Of-Conversions.
Functions of the ADC module include:
• 12-bit ADC core with built-in dual sample-and-hold (S/H)
• Simultaneous sampling or sequential sampling modes
• Full range analog input: 0 V to 3.3 V fixed, or V
REFHI
/V
REFLO
ratiometric. The digital value of the input
analog voltage is derived by:
– Internal Reference (V
REFLO
= V
SSA
. V
REFHI
must not exceed V
DDA
when using either internal or
external reference modes.)
– External Reference (V
REFHI
/V
REFLO
connected to external references. V
REFHI
must not exceed V
DDA
when using either internal or external reference modes.)
• Up to 16-channel, multiplexed inputs
• 16 SOCs, configurable for trigger, sample window, and channel
• 16 result registers (individually addressable) to store conversion values
• Multiple trigger sources
– S/W – software immediate start
– ePWM 1–4
– GPIO XINT2
– CPU Timers 0/1/2
– ADCINT1/2
• 9 flexible PIE interrupts, can configure interrupt request after any conversion
Copyright © 2008–2013, Texas Instruments Incorporated Peripherals 49
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