PIC18F4431-E/P Microchip Technology, PIC18F4431-E/P Datasheet - Page 163

• Manufacturer Part Number: PIC18F4431-E/P
• Description: IC MCU FLASH 8KX16 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4431-E/P

• Core Size: 8-Bit
• Program Memory Size: 16KB (8K x 16)
• 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
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC18
• No. Of I/o's: 36
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: EUSART, I2C, SPI, SSP
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 9 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: DVA18XP400 - DEVICE ADAPTER 18F4220 PDIP 40LDACICE0206 - ADAPTER MPLABICE 40P 600 MIL
• Lead Free Status / Rohs Status: Details

17.2.2
Position measurement resolution depends on how
often the Position Counter register, POSCNT, is
incremented. There are two QEI Update modes to
measure the rotor’s position: QEI x2 and QEI x4.
TABLE 17-4:
17.2.2.1
QEI x2 Update mode is selected by setting the QEI
Mode Select bits (QEIM<2:0>) to ‘001’ or ‘010’. In this
mode, the QEI logic detects every edge on the QEA
input only. Every rising and falling edge on the QEA
signal clocks the position counter.
The position counter can be reset by either an input on
the INDX pin (QEIM<2:0> = 001), or by a period match,
even when the POSCNT register pair equals MAXCNT
(QEIM<2:0> = 010).
17.2.2.2
QEI x4 Update mode provides for a finer resolution of
the rotor position, since the counter increments or
decrements more frequently for each QEA/QEB input
pulse pair than in QEI x2 mode. This mode is selected
by setting the QEI mode select bits to ‘101’ or ‘110’. In
QEI x4, the phase measurement is made on the rising
and the falling edges of both QEA and QEB inputs. The
position counter is clocked on every QEA and QEB
edge.
Like QEI x2 mode, the position counter can be reset by
an input on the pin (QEIM<2:0> = 101), or by the period
match event (QEIM<2:0> = 010).
 2010 Microchip Technology Inc.
Note 1:
QEIM<2:0>
000
001
010
011
100
101
110
111
QEI module is disabled. The position
counter and the velocity measurement
functions are fully disabled in this mode.
QEI MODES
QEI x2 Update Mode
QEI x4 Update Mode
index pulse
index pulse
x2 update/
x2 update/
x4 update/
x4 update/
Mode/
Reset
period
match
period
match
QEI MODES
—
—
—
—
QEI disabled.
Two clocks per QEA
pulse. INDX resets
POSCNT.
Two clocks per QEA pulse.
POSCNT is reset by the
period match (MAXCNT).
Unused.
Unused.
Four clocks per QEA and
QEB pulse pair.
INDX resets POSCNT.
Four clocks per QEA and
QEB pulse pair.
POSCNT is reset by the
period match (MAXCNT).
Unused.
Description
(1)
PIC18F2331/2431/4331/4431
17.2.3
The Position Counter register pair (POSCNTH:
POSCNTL) acts as an integrator, whose value is propor-
tional to the position of the sensor rotor that corresponds
to the number of active edges detected. POSCNT can
either increment or decrement, depending on a number
of selectable factors which are decoded by the QEI logic
block. These include the Count mode selected, the
phase relationship of QEA to QEB (“lead/lag”), the
direction of rotation and if a Reset event occurs. The
logic is detailed in the sections that follow.
17.2.3.1
In the first step, the active edges of QEA and QEB are
detected, and the phase relationship between them is
determined. The position counter is changed based on
the selected QEI mode.
In QEI x2 Update mode, the position counter
increments or decrements on every QEA edge based
on the phase relationship of the QEA and QEB signals.
In QEI x4 Update mode, the position counter
increments or decrements on every QEA and QEB
edge based on the phase relationship of the QEA and
QEB signals. For example, if QEA leads QEB, the
position counter is incremented by ‘1’. If QEB lags
QEA, the position counter is decremented by ‘1’.
17.2.3.2
The QEI control logic generates a signal that sets the
UP/DOWN bit (QEICON<5>); this, in turn, determines
the direction of the count. When QEA leads QEB,
UP/DOWN is set (= 1) and the position counter
increments on every active edge. When QEA lags
QEB, UP/DOWN is cleared and the position counter
decrements on every active edge.
TABLE 17-5:
QEA Rising
QEA Falling
QEB Rising
QEB Falling
Note 1:
Detected
Current
Signal
When UP/DOWN = 1, the position counter
is incremented. When UP/DOWN = 0, the
position counter is decremented.
QEI OPERATION
Edge and Phase Detect
Direction of Count
QEA QEB QEA QEB
DIRECTION OF ROTATION
x
x
Rising
Previous Signal
Detected
x
x
x
x
Falling
DS39616D-page 163
x
x
Cntrl.
Pos.
DEC
DEC
DEC
DEC
INC
INC
INC
INC
(1)