PIC16C74A-20/L Microchip Technology, PIC16C74A-20/L Datasheet - Page 125

• Manufacturer Part Number: PIC16C74A-20/L
• Description: IC MCU OTP 4KX14 A/D PWM 44PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C74A-20/L

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: OTP
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 6 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Controller Family/series: PIC16C
• No. Of I/o's: 33
• Ram Memory Size: 192Byte
• Cpu Speed: 10MHz
• No. Of Timers: 3
• Interface: I2C, SPI, USART
• Embedded Interface Type: I2C, SPI, USART
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164309 - MODULE SKT FOR PM3 44PLCC444-1001 - DEMO BOARD FOR PICMICRO MCUDVA16XL441 - ADAPTER DEVICE ICE 44PLCCDV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

13.8
An A/D conversion can be started by the “special event
trigger” of the CCP2 module (CCP1 on the PIC16C72
only). This requires that the CCP2M3:CCP2M0 bits
(CCP2CON<3:0>) be programmed as 1011 and that
the A/D module is enabled (ADON bit is set). When the
trigger occurs, the GO/DONE bit will be set, starting the
A/D conversion, and the Timer1 counter will be reset to
zero. Timer1 is reset to automatically repeat the A/D
acquisition period with minimal software overhead
(moving the ADRES to the desired location). The
appropriate analog input channel must be selected and
the minimum acquisition done before the “special event
trigger” sets the GO/DONE bit (starts a conversion).
If the A/D module is not enabled (ADON is cleared),
then the “special event trigger” will be ignored by the
A/D module, but will still reset the Timer1 counter.
13.9
If the input voltage exceeds the rail values (V
by greater than 0.2V, then the accuracy of the conver-
sion is out of specification.
An external RC filter is sometimes added for anti-alias-
ing of the input signal. The R component should be
selected to ensure that the total source impedance is
kept under the 10 k recommended specification. Any
external components connected (via hi-impedance) to
an analog input pin (capacitor, zener diode, etc.) should
have very little leakage current at the pin.
13.10
The ideal transfer function of the A/D converter is as
follows: the first transition occurs when the analog input
voltage (V
1997 Microchip Technology Inc.
Note:
Use of the CCP Trigger
Connection Considerations
Transfer Function
Applicable Devices
72 73 73A 74 74A 76 77
Applicable Devices
72 73 73A 74 74A 76 77
Applicable Devices
72 73 73A 74 74A 76 77
AIN
In the PIC16C72, the "special event trig-
ger" is implemented in the CCP1 module.
) is Analog V
REF
/256 (Figure 13-5).
SS
or V
DD
)
FIGURE 13-5: A/D TRANSFER FUNCTION
13.11
A very good reference for understanding A/D convert-
ers is the "Analog-Digital Conversion Handbook" third
edition,
0-13-03-2848-0).
FEh
FFh
04h
03h
02h
01h
00h
References
published
Analog input voltage
by
PIC16C7X
Prentice
DS30390E-page 125
Hall
(ISBN