PIC16C781-E/P Microchip Technology, PIC16C781-E/P Datasheet - Page 88

• Manufacturer Part Number: PIC16C781-E/P
• Description: IC MCU OTP 1KX14 W/AD 20DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C781-E/P

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 13
• Program Memory Size: 1.75KB (1K x 14)
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x8b; D/A 1x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• For Use With: DVA16XP202 - ADAPTER DEVICE PIC16C781/782DM163012 - BOARD DEMO PICDEM FOR 16C781/782AC164028 - MODULE SKT PROMATEII 20SOIC/DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

PIC16C781/782
11.2
The following example demonstrates calibration of the
OPA module as an Operational Amplifier.
EXAMPLE 11-1:
;*
;*
;*
;*
;*
CAL_LOOP
The following example demonstrates how to configure
and calibrate the OPA module as a Voltage Comparator.
EXAMPLE 11-2:
;*
;*
;*
;*
;*
CAL_LOOP
DS41171A-page 86
This code block will configure the OPA
BANKSEL
MOVLW
MOVWF
BCF
BSF
BTFSC
GOTO
MOVLW
BTFSS
CLRW
RETURN
This code block will configure the OPA
Routine returns w=0 if calibration good.
BANKSEL
MOVLW
MOVWF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BTFSC
GOTO
MOVLW
BTFSS
CLRW
BSF
RETURN
module as an Op Amp, 2 MHz GBWP, and
calibrated for a common mode voltage of
1.2V. Routine returns w=0 if
calibration good.
module as a voltage comparator, slow
speed, and calibrated for a common mode
voltage of 2.5 V (assumes VDD=5V).
Configuration as OPAMP or
Comparator
OPACON
B’10000001’
OPACON
CALCON,CALREF; Set 1.2V
CALCON,CAL
CALCON,CAL
CAL_LOOP
ERROR_FLAG
CALCON,CALERR; Test for error
OPACON
B’10000000’
OPACON
CALCON,CALREF; Common mode=DAC
H’0x80’
DAC
B’10000000’
DACON0
CALCON,CAL
CALCON,CAL
CAL_LOOP
ERROR_FLAG
CALCON,CALERR; Test for error
OPACON,CMPEN ; Comparator mode
CALIBRATION FOR
OPAMP MODE
CALIBRATION FOR
COMPARATOR MODE
; Op Amp mode &
; Test for end
; Select Bank 2
; 2 MHz GBWP
; Start
; Test for end
; If not, wait
; If no, return 0
; enable DAC,
; VDD ref
; If not, wait
; If no, return 0
; Select Bank 2
; Op Amp mode,
; slow
; DAC at VDD/2
; Start
Preliminary
11.3
A device RESET forces all registers to their RESET
state. This disables the OPA module and clears any
calibration.
11.4
Common AC and DC performance specifications for
the OPA module:
• Common Mode Voltage Range
• Leakage Current
• Input Offset Voltage
• Open Loop Gain
• Gain Bandwidth Product
Common mode voltage range is the specified voltage
range for the OPA+ and OPA- inputs, for which the OPA
module will perform to within its specifications. The
OPA module is designed to operate with input voltages
between 0 and V
voltages greater than V
guaranteed.
Leakage current is a measure of the small source or
sink currents on the OPA+ and OPA- inputs. To mini-
mize the effect of leakage currents, the effective imped-
ances connected to the OPA+ and OPA- inputs should
be kept as small as possible and equal.
Input offset voltage is a measure of the voltage differ-
ence between the OPA+ and OPA- inputs in a closed
loop circuit with the OPA in its linear region. The offset
voltage will appear as a DC offset in the output equal to
the input offset voltage, multiplied by the gain of the cir-
cuit. The input offset voltage is also affected by the
Common mode voltage. The OPA has an automatic
calibration module which can minimize the input offset
voltage of the module.
Open loop gain is the ratio of the output voltage to the
differential input voltage, (OPA+) - (OPA-). The gain is
greatest at DC and falls off with frequency.
Gain Bandwidth Product or GBWP is the frequency
at which the open loop gain falls off to 0 dB. The lower
GBWP is optimized for systems requiring low fre-
quency response and low power consumption.
Effects of RESET
OPA Module Performance
DD
-1.4V. Behavior for Common mode
DD
2001 Microchip Technology Inc.
-1.4V, or below 0V, are not