PIC18LF2431-I/SO Microchip Technology, PIC18LF2431-I/SO Datasheet - Page 177

• 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

16.2.6
The velocity pulse generator, in conjunction with the
IC1 and the synchronous TMR5 (in synchronous
operation), provides a method for high accuracy speed
measurements at both low and high mechanical motor
speeds. The Velocity mode is enabled when the VELM
bit is cleared (= 0) and QEI is set to one of its operating
modes (see Table 16-6).
To optimize register space, the Input Capture
Channel 1 (IC1) is used to capture TMR5 counter
values. Input Capture Buffer register, CAP1BUF, is
redefined in Velocity Measurement mode, VELM = 0,
as the Velocity Register Buffer (VELRH, VELRL).
TABLE 16-6:
FIGURE 16-12:
© 2007 Microchip Technology Inc.
QEIM<2:0>
CAP1/INDX
CAP2/QEA
001
010
101
110
CAP3/QEB
VELOCITY MEASUREMENT
x2 Velocity Event mode. The velocity
pulse is generated on every QEA edge.
x4 Velocity Event mode. The velocity
pulse is generated on every QEA and
QEB active edge.
VELOCITY PULSES
VELOCITY MEASUREMENT BLOCK DIAGRAM
Velocity Event Mode
QEB
QEA
INDX
Control
Logic
Velocity Event
QEI
Direction
Clock
PIC18F2331/2431/4331/4431
Preliminary
Postscaler
Reset
Logic
Position
Counter
TMR5 Reset
16.2.6.1
The event pulses are reduced by a fixed ratio by the
velocity pulse divider. The divider is useful for
high-speed measurements where the velocity events
happen frequently. By producing a single output pulse
for a given number of input event pulses, the counter
can track larger pulse counts (i.e., distance travelled)
for a given time interval. Time is measured by utilizing
the TMR5 time base.
Each velocity pulse serves as a capture pulse. With the
TMR5 in Synchronous Timer mode, the value of TMR5
is captured on every output pulse of the postscaler. The
counter is subsequently reset to ‘0’. TMR5 is reset
upon a capture event.
Figure 16-13 shows the velocity measurement timing
diagram.
Velocity Capture
Velocity Event Timing
(VELR Register)
TMR5
IC1
16
Clock
DS39616C-page 175
Velocity Mode
T
CY