PIC18F4431-E/PT Microchip Technology, PIC18F4431-E/PT Datasheet - Page 254

• Manufacturer Part Number: PIC18F4431-E/PT
• Description: IC MCU FLASH 8KX16 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4431-E/PT

• Core Size: 8-Bit
• Program Memory Size: 16KB (8K x 16)
• Oscillator Type: Internal
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, Power Control PWM, QEI, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 9x10b
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 44-TQFP, 44-VQFP
• Controller Family/series: PIC18
• No. Of I/o's: 36
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 40MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC18F2331/2431/4331/4431
20.1.3
The ACMOD<1:0> bits control the sequencing of the
A/D conversions. When ACSCH = 0, the A/D is
configured to sample and convert a single channel.
The ACMOD bits select which group to perform the
conversions and the GxSEL<1:0> bits select which
channel in the group is to be converted. If Single-shot
mode is enabled, the A/D interrupt flag will be set after
the channel is converted. If Continuous Loop mode is
enabled, the A/D interrupt flag will be set according to
the ADRS<1:0> bits.
When ACSHC = 1, multiple channel sequencing is
enabled and two sub-modes can be selected. The first
mode is Sequential mode with two settings. The first
setting is called SEQM1 and first samples and converts
the selected Group A channel and then samples and
converts the selected Group B channel. The second
mode is called SEQM2, and it samples and converts a
Group A channel, Group B channel, Group C channel
and finally a Group D channel.
The second multiple channel sequencing sub-mode is
Simultaneous Sampling mode. In this mode, there are
also two settings. The first setting is called STNM1 and
uses the two sample and hold circuits on the A/D
module. The selected Group A and B channels are
simultaneously sampled and then the Group A channel
is converted followed by the conversion of the Group B
channel. The second setting is called STNM2 and
starts the same as STNM1 but follows it with a
simultaneous sample of Group C and D channels. The
A/D module will then convert the Group C channel
followed by the Group D channel.
20.1.4
The PIC18F2331/2431/4331/4431 devices are capable
of triggering conversions from many different sources.
The same method used by all other microcontrollers of
setting the GO/DONE bit still works. The other trigger
sources are:
• RC3/INT0 pin
• Timer5 Overflow
• Input Capture 1 (IC1)
• CCP2 Compare Match
• Power Control PWM rising edge
These triggers are enabled using the SSRC<4:0> bits
(ADCON3<4:0>). Any combination of the five sources
can trigger a conversion by simply setting the corre-
sponding bit in ADCON3. When the trigger occurs, the
GO/DONE bit is automatically set by the hardware and
then cleared once the conversion completes.
DS39616B-page 252
CONVERSION SEQUENCING
TRIGGERING A/D CONVERSIONS
Preliminary
20.1.5
The following steps should be followed to initialize the
A/D module:
1.
2.
3.
4.
5.
6.
Configure the A/D module:
a)
b)
c)
d)
e)
Configure A/D interrupt (if required):
a)
b)
c)
d)
e)
f)
Turn On ADC:
a)
b)
Start sample/conversion sequence:
a)
b)
Wait
complete using one of the following options:
a)
b)
c)
Read A/D results, clear ADIF flag, reconfigure
trigger.
Configure analog pins, voltage reference
and digital I/O
Select A/D input channels
Select A/D Auto-conversion mode
(Single-shot or Continuous Loop)
Select A/D conversion clock
Select A/D conversion trigger
Set GIE bit
Set PEIE bit
Set ADIE bit
Clear ADIF bit
Select A/D trigger setting
Select A/D interrupt priority
Set ADON bit in ADCON0 register
Wait the required power-up setup time,
about 5-10 µs
Sample for a minimum of 2T
conversion by setting the GO/DONE bit.
The GO/DONE bit is set by the user in
software or by the module if initiated by a
trigger.
If T
then setting the GO/DONE bit starts a
sample period of the T
a conversion.
Poll for the GO/DONE bit to be cleared if in
Single-shot mode.
Wait for the A/D interrupt flag (ADIF) to be
set.
Poll for the BFEMT bit to be cleared to
signify that at least the first conversion has
completed.
A/D MODULE INITIALIZATION
STEPS
for
ACQ
is assigned a value (multiple of T
A/D
conversion/conversions
 2003 Microchip Technology Inc.
ACQ
value, then starts
AD
and start
AD
to
),