UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
173 of 268
NXP Semiconductors
UM10413
MPT612 User manual
19.3 Pin
description
gives a brief summary of each of ADC-related pin.
19.4 Register
description
The ADC registers are shown in
Table 158. ADC pin description
Pin
Type
Description
AD7:0
input
analog inputs.
The ADC cell can measure the voltage on any of these input signals.
Note that these analog inputs are always connected to their pins, even if the pin
function select register assigns them to port pins. A simple self-test of the ADC can be
done by driving these pins as port outputs.
If the ADC is used, signal levels on analog input pins must not be above the level of
V
3A
at any time. Otherwise, ADC readings are invalid. If the ADC is not used in an
application, the pins associated with the A-to-D inputs can be used as 5 V tolerant
digital IO pins.
Remark:
while the ADC pins are specified as 5 V tolerant (see
analog multiplexing in ADC block is not. More than 3.3 V (V
DD(ADC)
) must not be
applied to any pin that is selected as an ADC input, or the ADC reading will be
incorrect. If for example AD0 and AD1 are used as the ADC0 inputs and voltage on
AD0 = 4.5 V while AD1 = 2.5 V, an excessive voltage on AD0 can cause an incorrect
reading of AD1, although the AD1 input voltage is within the right range.
V
DD(ADC)
, GND
ADC
power
analog power and ground.
Must nominally be the same voltages as V
DD
and GND
but must be isolated to minimize noise and error. V
DD(ADC)
also provides the ADC
voltage reference level (V
Ref
).
Remark:
If ADC is not used, V
DD(ADC)
must still be tied to V
DD(IO)
, and GND
ADC
must
be grounded. These pins must not be left floating.
Table 159. ADC registers
Generic
name
Description
Access
Reset value
AD0
Address
and name
ADCR
A/D control register. ADCR must be written to select operating
mode before A/D conversion can occur.
R/W
0x0000 0001
0xE003 4000
AD0CR
ADGDR
A/D global data register. Contains ADC’s DONE bit and result
of the most recent A/D conversion.
R/W
n/a
0xE003 4004
AD0GDR
ADSTAT
A/D status register. Contains DONE and OVERRUN flags for
all A/D channels and A/D interrupt flag.
RO
0x0000 0000
0xE003 4030
AD0STAT
ADINTEN
A/D interrupt enable register. Contains enable bits that allow
the DONE flag of each A/D channel to be included or
excluded from contributing to generation of an A/D interrupt.
R/W
0x0000 0100
0xE003 400C
AD0INTEN
ADDR3
A/D channel 3 data register. Contains the result of the most
recent conversion completed on channel 3.
RO
n/a
0xE003 401C
AD0DR3
ADDR4
A/D channel 4 data register. Contains the result of the most
recent conversion completed on channel 4.
RO
n/a
0xE003 4020
AD0DR4
ADDR5
A/D channel 5 data register. Contains the result of the most
recent conversion completed on channel 5.
RO
n/a
0xE003 4024
AD0DR5
ADDR6
A/D channel 6 data register. Contains the result of the most
recent conversion completed on channel 6.
RO
n/a
0xE003 4028
AD0DR6
ADDR7
A/D channel 7 data register. Contains the result of the most
recent conversion completed on channel 7.
RO
n/a
0xE003 402C
AD0DR7