PIC18LF2431-I/SO Microchip Technology, PIC18LF2431-I/SO Datasheet - Page 174

• Manufacturer Part Number: PIC18LF2431-I/SO
• Description: IC MCU FLASH 8KX16 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF2431-I/SO

• 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: 24
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Controller Family/series: PIC18
• No. Of I/o's: 24
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18LF
• 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: 24
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DM183021, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC18F2331/2431/4331/4431
16.2.3.3
The position counter will continue to increment or dec-
rement until one of the following events takes place.
The type of event and the direction of rotation when it
happens determines if a register Reset or update
occurs.
1.
2.
The value of the position counter is not affected during
QEI mode changes, nor when the QEI is disabled
altogether.
DS39616C-page 172
An index pulse is detected on the INDX input
(QEIM2:QEIM0 = 001).
If the encoder is traveling in the forward direc-
tion, POSCNT is reset (00h) on the next clock
edge after the index marker, INDX, has been
detected. The position counter resets on the
QEA or QEB edge once the INDX rising edge
has been detected.
If the encoder is traveling in the reverse direc-
tion, the value in the MAXCNT register is loaded
into POSCNT on the next quadrature pulse
edge (QEA or QEB) after the falling edge on
INDX has been detected.
A POSTCNT/MAXCNT period match occurs
(QEIM2:QEIM0 = 010).
If the encoder is traveling in the forward direc-
tion, POSCNT is reset (00h) on the next clock
edge when POSCNT = MAXCNT. An interrupt
event is triggered on the next T
(see Figure 16-10)
If the encoder is traveling in the reverse
direction and the value of POSCNT reaches
00h, POSCNT is loaded with the contents of the
MAXCNT register on the next clock edge. An
interrupt event is triggered on the next T
the load operation (see Figure 16-10).
Reset and Update Events
CY
after the Reset
CY
after
Preliminary
16.2.4
The position counter interrupt occurs and the interrupt
flag (IC2QEIF) is set, based on the following events:
• A POSCNT/MAXCNT period match event
• A POSCNT rollover (FFFFh to 0000h) in Period
• An index pulse detected on INDX
The interrupt timing diagrams for IC2QEIF are shown in
Figure 16-10 and Figure 16-11.
When the direction has changed, the direction change
interrupt flag (IC3DRIF) is set on the following T
clock (see Figure 16-10).
If the position counter rolls over in Index mode, the
QERR bit will be set.
16.2.5
The quadrature input signals, QEA and QEB, may vary
in quadrature frequency. The minimum quadrature
input period, T
The position count rate, F
the rotor’s RPM, line count D and QEI Update mode (x2
versus x4); that is,
EQUATION 16-1:
The maximum position count rate (i.e., x4 QEI
Update mode, D = 1024) with F
to 2.5 MHz, which corresponds to F
Figure 16-9 shows QEA and QEB quadrature input
timing when sampled by the noise filter.
(QEIM2:QEIM0 = 010 or 110)
mode only (QEIM2:QEIM0 = 010 or 110)
Note:
QEI INTERRUPTS
QEI SAMPLE TIMING
The number of incremental lines in the
position encoder is typically set at D = 1024
and the QEI Update mode = x4.
QEI
, is 16 T
F
POS
= 4D • RPM
© 2007 Microchip Technology Inc.
POS
CY
.
, is directly proportional to
60
CY
= 10 MIPS is equal
QEI
of 625 kHz.
CY