PIC18F2420-I/ML Microchip Technology, PIC18F2420-I/ML Datasheet - Page 233

• Manufacturer Part Number: PIC18F2420-I/ML
• Description: IC PIC MCU FLASH 8KX16 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2420-I/ML

• Program Memory Type: FLASH
• Program Memory Size: 16KB (8K x 16)
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: EUSART, I2C, MSSP, SPI
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 25
• 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, DM163014, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• Package: 28QFN EP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28QFN4 - SOCKET TRANS ICE 28QFN W/CABLEAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

19.6
Figure 19-4 shows the operation of the A/D Converter
after the GO/DONE bit has been set and the
ACQT<2:0> bits are cleared. A conversion is started
after the following instruction to allow entry into Sleep
mode before the conversion begins.
Figure 19-5 shows the operation of the A/D Converter
after the GO/DONE bit has been set and the
ACQT<2:0> bits are set to ‘010’, and selecting a 4 T
acquisition time before the conversion starts.
Clearing the GO/DONE bit during a conversion will abort
the current conversion. The A/D Result register pair will
NOT be updated with the partially completed A/D
conversion sample. This means the ADRESH:ADRESL
registers will continue to contain the value of the last
completed conversion (or the last value written to the
ADRESH:ADRESL registers).
FIGURE 19-4:
FIGURE 19-5:
© 2008 Microchip Technology Inc.
(Holding capacitor continues
acquiring input)
Set GO/DONE bit
1
T
CY
Set GO/DONE bit
T
A/D Conversions
Holding capacitor is disconnected from analog input (typically 100 ns)
ACQT
Acquisition
Automatic
- T
2
Time
AD
Conversion starts
Cycles
T
AD
3
1 T
A/D CONVERSION T
A/D CONVERSION T
AD
b9
4
2 T
Conversion starts
(Holding capacitor is disconnected)
AD
b8
1
3 T
AD
b9
2
b7
4 T
On the following cycle:
ADRESH:ADRESL are loaded, GO/DONE bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
AD
PIC18F2420/2520/4420/4520
b8
3
AD
AD
b6
5 T
On the following cycle:
ADRESH:ADRESL are loaded, GO/DONE bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
CYCLES (ACQT<2:0> = 000, T
CYCLES (ACQT<2:0> = 010, T
AD
AD
b5
b7
4
6 T
T
AD
b4
5
b6
AD
7 T
Cycles
After the A/D conversion is completed or aborted, a
2 T
be started. After this wait, acquisition on the selected
channel is automatically started.
19.7
The discharge phase is used to initialize the value of
the capacitor array. The array is discharged before
every sample. This feature helps to optimize the unity-
gain amplifier, as the circuit always needs to charge the
capacitor array, rather than charge/discharge based on
previous measure values.
AD
b3
b5
Note:
6
AD
8
wait is required before the next acquisition can
T
AD
b4
b2
Discharge
7
9 T
The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
AD
b3
8
b1
10
ACQ
T
ACQ
AD
b0
b2
9
11
= 0)
= 4 T
T
AD
10
Discharge
b1
AD
1
)
b0
11
DS39631E-page 231
T
Discharge
AD
1