PIC18LF2539T-I/SO Microchip Technology, PIC18LF2539T-I/SO Datasheet - Page 116

• Manufacturer Part Number: PIC18LF2539T-I/SO
• Description: IC MCU FLASH 12KX16 EE AD 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF2539T-I/SO

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 21
• Program Memory Size: 24KB (12K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1408 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)
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1408 B
• Interface Type: I2C, SPI, AUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 16 bit
• 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: DV164005, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC18FXX39
14.3
A sine table, stored in the ProMPT kernel, is used as
the basis for synthesizing the DC bus using the PWM
modules. The table values are accessed in sequence
and scaled based on the frequency or the speed at
which the motor is intended to run. The intended fre-
quency input can be from an A/D channel or a digital
value.
Parameters in the ProMPT modules can be accessed
using the pre-defined Application Program Interface
(API) methods. A list of the APIs is given in
Section 14.3.3.
For example, to run the motor at 40 Hz, the user would
invoke the PromMPT_SetFrequency API:
i = ProMPT_SetFrequency(40);
where i is an unsigned character variable. In this case,
if i = 0 on return, the command has been successfully
executed. If the frequency input is out of range, or if
there is an error in setting the frequency, i is returned
with a value of FFh.
Similarly, to check the frequency set by the ProMPT
kernel, use the ProMPT_GetFrequency API:
i = ProMPT_GetFrequency(void);
where i is an unsigned character variable. Upon return
from the ProMPT kernel, i will contain the frequency
value in the ProMPT kernel.
14.3.1
The ProMPT kernel contains a default V/F curve stored
in memory. The default curve is linear, as shown in
Figure 14-2. Table 14-1 shows the data points used to
construct the curve.
Users may require a different V/F curve for their appli-
cation, based on the load on the motor, or based on the
characteristics of the motor used. The curve can be
changed in the application program using the API
method SetVFCurve(X,Y), where X is the frequency
and Y is the level of modulation of the DC bus voltage.
As a rule, in customizing the curve, the input frequency
corresponding to the point on the V/F curve that gives
100% modulation should match the motor’s rated fre-
quency. Similarly, full modulation should occur at the
motor’s rated input voltage. (See Figure 14-2 for
details.)
Examples of the characteristics for V/F curves for typi-
cal motor applications are shown in Section 14-2
(page 115).
14.3.2
Frequency: The frequency (in Hz) of the supply
current for steady state motor operation.
Modulation: The level of modulation (in percentage)
applied to the DC supply voltage by the PWM through
the H-bridge to produce AC drive current.
DS30485A-page 114
Software Interface
THE V/F CURVE
PARAMETERS DEFINED BY THE
ProMPT API METHODS
Preliminary
Acceleration rate: The rate of increase of motor
speed, achieved by ramping up the supply frequency.
Expressed in Hz/s.
Deceleration rate: The rate of decrease of motor
speed, achieved by ramping down the supply
frequency. Expressed in Hz/s.
Boost: The mode for starting a stopped motor by vary-
ing the supply current frequency and modulation until
steady state speed is reached. Boost is defined in
terms of a frequency, a starting and ending modulation,
and a time interval for the transition between the two.
PWM Frequency: The sampling rate (in kHz) at which
the PWM module operates.
FIGURE 14-2:
TABLE 14-1:
150
125
100
Frequency (Hz)
75
50
25
0
0
V
should equal
at 100% modulation
104
112
120
128
rated
16
24
32
40
48
56
64
72
80
88
96
0
8
20
of motor
DATA POINTS FOR THE
DEFAULT V/F CURVE
40
Input Frequency (Hz)
DEFAULT V/F CURVE FOR
THE ProMPT KERNEL
 2002 Microchip Technology Inc.
60
80
% Modulation
f
should equal f at
100% modulation
rated
100
100
133
133
133
133
133
133
133
133
110
14
28
42
57
71
86
of motor
0
120
140