PIC18F65K90T-I/MR Microchip Technology, PIC18F65K90T-I/MR Datasheet - Page 417

• Manufacturer Part Number: PIC18F65K90T-I/MR
• Description: 32kB Flash, 2kB RAM, 1kB EE, NanoWatt XLP, LCD 64 QFN 9x9x0.9mm T/R
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F65K90T-I/MR

• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 32 KB
• Data Ram Size: 2 KB
• Interface Type: I2C, SPI
• Maximum Clock Frequency: 64 MHz
• Number Of Timers: 8
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 16 Channel
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 53
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN Exposed Pad
• Lead Free Status / Rohs Status: Details

EXAMPLE 27-3:
 2009-2011 Microchip Technology Inc.
#include "p18cxxx.h"
#define COUNT 25
#define ETIME COUNT*2.5
#define DELAY for(i=0;i<COUNT;i++)
#define ADSCALE 1023
#define ADREF 3.3
#define RCAL .027
int main(void)
{
//assume CTMU and A/D have been setup correctly
//see Example 25-1 for CTMU & A/D setup
setup();
CTMUCONHbits.CTMUEN = 1;
}
int i;
int j = 0;
unsigned int Vread = 0;
float CTMUISrc, CTMUCap, Vavg, VTot, Vcal;
for(j=0;j<10;j++)
{
}
Vavg = (float)(VTot/10.000);
Vcal = (float)(Vavg/ADSCALE*ADREF);
CTMUISrc = Vcal/RCAL;
CTMUCap = (CTMUISrc*ETIME/Vcal)/100;
CTMUCONHbits.IDISSEN = 1;
DELAY;
CTMUCONHbits.IDISSEN = 0;
CTMUCONLbits.EDG1STAT = 1;
DELAY;
CTMUCONLbits.EDG1STAT = 0;
PIR1bits.ADIF = 0;
ADCON0bits.GO=1;
while(!PIR1bits.ADIF);
Vread = ADRES;
PIR1bits.ADIF = 0;
VTot += Vread;
CAPACITANCE CALIBRATION ROUTINE
//@ 8MHz INTFRC = 62.5 us.
//time in uS
//for unsigned conversion 10 sig bits
//Vdd connected to A/D Vr+
//R value is 4200000 (4.2M)
//scaled so that result is in
//1/100th of uA
//index for loop
//Enable the CTMU
//drain charge on the circuit
//wait 125us
//end drain of circuit
//Begin charging the circuit
//using CTMU current source
//wait for 125us
//Stop charging circuit
//make sure A/D Int not set
//and begin A/D conv.
//Wait for A/D convert complete
//Get the value from the A/D
//Clear A/D Interrupt Flag
//Add the reading to the total
//Average of 10 readings
//CTMUISrc is in 1/100ths of uA
PIC18F87K90 FAMILY
DS39957D-page 417