PIC16LC924-04/PT Microchip Technology, PIC16LC924-04/PT Datasheet - Page 85

• Manufacturer Part Number: PIC16LC924-04/PT
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,TQFP,64PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16LC924-04/PT

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: I²C, SPI
• Peripherals: LCD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 7KB (4K x 14)
• Program Memory Type: OTP
• Ram Size: 176 x 8
• Voltage - Supply (vcc/vdd): 2.5 V ~ 6 V
• Data Converters: A/D 5x8b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 64-TFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

12.4.1
Not all applications require a result with 8-bits of reso-
lution, but may instead require a faster conversion time.
The A/D module allows users to make the trade-off of
conversion speed to resolution. Regardless of the res-
olution required, the acquisition time is the same. To
speed up the conversion, the clock source of the A/D
module may be switched so that the T
the minimum specified time (see the applicable electri-
cal specification). Once the T
mum specified time, all the following A/D result bits are
not valid (see A/D Conversion Timing in the Electrical
Specifications section.) The clock sources may only be
switched between the three oscillator versions (cannot
be switched from/to RC). The equation to determine
the time before the oscillator can be switched is as fol-
lows:
EXAMPLE 12-3: 4-BIT vs. 8-BIT CONVERSION TIMES
T
T
2T
1997 Microchip Technology Inc.
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OSC
Conversion time = 2T
Where: N = number of bits of resolution required.
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+ N • T
FASTER CONVERSION - LOWER
RESOLUTION TRADE-OFF
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+ (8 - N)(2T
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+ N • T
OSC
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)
time violates the mini-
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+ (8 - N)(2T
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time violates
OSC
)
Since the T
user must use some method (a timer, software loop,
etc.) to determine when the A/D oscillator may be
changed. Example 12-3 shows a comparison of time
required for a conversion with 4-bits of resolution, ver-
sus the 8-bit resolution conversion. The example is for
devices operating at 8 MHz (The A/D clock is pro-
grammed for 32T
after 6T
The 2T
the last 4-bits will not be converted to correct values.
Freq. (MHz)
OSC
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8
8
8
, the A/D clock is programmed for 2T
AD
violates the minimum T
is based from the device oscillator, the
OSC
), and assumes that immediately
12.5 ns
10.6 s
1.6 s
4-bit
PIC16C9XX
Resolution
DS30444E - page 85
AD
time, therefore
125 ns
1.6 s
16 s
8-bit
OSC
.