PIC16F871-I/PT Microchip Technology Inc., PIC16F871-I/PT Datasheet - Page 86

• Manufacturer Part Number: PIC16F871-I/PT
• Description: 44 PIN, 7 KB FLASH, 128 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F871-I/PT

• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 33
• Interface: USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TQFP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16F870/871
10.4
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. That is, 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). After the A/D conversion
is aborted, a 2 T
FIGURE 10-3:
10.4.1
The ADRESH:ADRESL register pair is the location
where the 10-bit A/D result is loaded at the completion of
the A/D conversion. This register pair is 16-bits wide.
The A/D module gives the flexibility to left or right justify
the 10-bit result in the 16-bit result register. The A/D For-
FIGURE 10-4:
DS30569B-page 84
A/D Conversions
A/D RESULT REGISTERS
T
CY
Set GO bit
Holding capacitor is disconnected from analog input (typically 100 ns)
7
to T
0000 00
AD
ADRESH
AD
wait is required before the next
Conversion starts
A/D CONVERSION T
A/D RESULT JUSTIFICATION
T
AD
Right Justified
1
2 1 0 7
ADFM = 1
T
AD
b9
2
10-bit Result
T
ADRESL
AD
b8
3
T
AD
b7
AD
4
0
CYCLES
T
AD
b6
10-bit Result
5
T
AD
b5
6
acquisition is started. After this 2 T
on the selected channel is automatically started. The
GO/DONE bit can then be set to start the conversion.
In Figure 10-3, after the GO bit is set, the first time
segment has a minimum of T
mat Select bit (ADFM) controls this justification.
Figure 10-4 shows the operation of the A/D result justifi-
cation. The extra bits are loaded with ‘0’. When an A/D
result will not overwrite these locations (A/D disable),
these registers may be used as two general purpose
8-bit registers.
T
ADRES is loaded
GO bit is cleared
ADIF bit is set
Holding capacitor is connected to analog input
AD
b4
Note:
7
7
T
AD
b3
ADRESH
8
The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
10-bit Result
T
AD
b2
ADFM = 0
9
Left Justified
T
0 7 6 5
AD
b1
10 T
 2003 Microchip Technology Inc.
ADRESL
CY
AD
b0
0000 00
11
and a maximum of T
AD
0
wait, acquisition
AD
.