PIC16F628A-E/P Microchip Technology, PIC16F628A-E/P Datasheet - Page 69

• Manufacturer Part Number: PIC16F628A-E/P
• Description: IC MCU FLASH 2KX14 EEPROM 18DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F628A-E/P

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 18-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Ram Size: 224 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 224 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• Data Rom Size: 128 B
• Height: 3.3 mm
• Length: 22.86 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 3 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3DBF648 - BOARD DAUGHTER ICEPIC3AC162053 - HEADER INTERFACE ICD,ICD2 18DIPACICE0202 - ADAPTER MPLABICE 18P 300 MIL
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

11.0
The Voltage Reference module consists of a 16-tap
resistor ladder network that provides a selectable volt-
age reference. The resistor ladder is segmented to pro-
vide two ranges of V
function to conserve power when the reference is not
being used. The VRCON register controls the opera-
tion of the reference as shown in Figure 11-1. The
block diagram is given in Figure 11-1.
11.1
The Voltage Reference module can output 16 distinct
voltage levels for each range.
REGISTER 11-1:
© 2009 Microchip Technology Inc.
VOLTAGE REFERENCE
MODULE
Voltage Reference Configuration
bit 7
bit 6
bit 5
bit 4
bit 3-0
REF
VRCON – VOLTAGE REFERENCE CONTROL REGISTER (ADDRESS: 9Fh)
bit 7
VREN: V
1 = V
0 = V
VROE: V
1 = V
0 = V
VRR: V
1 = Low range
0 = High range
Unimplemented: Read as ‘0’
VR<3:0>: V
When VRR = 1: V
When VRR = 0: V
Legend:
R = Readable bit
-n = Value at POR
values and has a power-down
R/W-0
VREN
REF
REF
REF
REF
REF
REF
REF
circuit powered on
circuit powered down, no I
is output on RA2 pin
is disconnected from RA2 pin
Range Selection bit
REF
Enable bit
Output Enable bit
R/W-0
VROE
Value Selection bits 0 ≤ VR <3:0> ≤ 15
REF
REF
= (VR<3:0>/ 24) * V
= 1/4 * V
R/W-0
VRR
W = Writable bit
‘1’ = Bit is set
DD
PIC16F627A/628A/648A
+ (VR<3:0>/ 32) * V
DD
U-0
—
drain
The equations used to calculate the output of the
Voltage Reference module are as follows:
The setting time of the Voltage Reference module must
be considered when changing the V
(Table 17-3). Example 11-1 demonstrates how voltage
reference is configured for an output voltage of 1.25V
with V
DD
if VRR = 1:
if VRR = 0:
DD
V
= 5.0V.
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-0
REF
VR3
DD
=
V
REF
⎛
⎝
V
DD
=
×
R/W-0
V
---------------------- -
VR2
R
1
-- -
4
⎞
⎠
<3:0>
24
+
V
---------------------- -
R
x = Bit is unknown
<3:0>
×
32
R/W-0
V
VR1
REF
DD
DS40044G-page 69
×
output
V
DD
R/W-0
VR0
bit 0