This document is a schematic for a digital clock that uses an ATMEGA328P microcontroller and a DS3231 real-time clock module. It includes four 7-segment displays driven by HDSP-5501 LED driver chips, four buttons for input, a buzzer, and a 16MHz crystal oscillator. The microcontroller is connected to the real-time clock module via the SCL and SDA pins for timekeeping. Power is supplied to most components from the 5V rail.

1. A A
B B
C C
1
1
2
2
3
3
4
4
TITLE:
DigitalClock RTC REV: 1.0
Date: 2020-03-26
Sheet: 1/1
Drawn By: Shivam Kurzekar
Company: -
ATMEGA328P-PU
U1
PC6 RESET#
1
PD0 RXD
2
PD1 TXD
3
INT0 PD2 4
INT1 PD3 5
T0 PD4 6
VCC
7
GND
8
PB6 XTAL1
9
PB7 XTAL2
10
T1 PD5 11
AIN0 PD6 12
AIN1 PD7 13
PCINT0 PB0 14
PCINT1 PB1 15
PCINT2 PB2 16
PCINT3 PB3 17
PCINT4 PB4 18
PCINT5 PB5 19
AVCC
20
AREF
21
GND
22
PC0 ADC0 23
PC1 ADC1 24
PC2 ADC2 25
PC3 ADC3 26
PC4 ADC4 27
PC5 ADC5 28
HDSP-5501
LED1
COM
3
f 9
g 10
e 1
d 2
COM
8
DP
5
c 4
b 6
a 7
HDSP-5501
LED2
COM
3
f 9
g 10
e 1
d 2
COM
8
DP
5
c 4
b 6
a 7
HDSP-5501
LED4
COM
3
f 9
g 10
e 1
d 2
COM
8
DP
5
c 4
b 6
a 7
HDSP-5501
LED3
COM
3
f 9
g 10
e 1
d 2
COM
8
DP
5
c 4
b 6
a 7
22pF
C1
22pF
C2
510K
R1
16MHz
X1
220
R2
220 R3
220 R4
220 R5
220 R6
220 R7
220 R8
220
R9
SW1
1 2
10K
R11
10K
R10
SW2
1 2
10K
R12
SW3
1 2
10K
R13
SW4 1 2
DS3231
U2
32K 1
SQW 2
SCL 3
SDA 4
VCC 5
GND 6
GMD12075YB-3V2700
BUZZER1
1
2
GND
+5V
GND
XTAL 1
XTAL 2
5V
5V
XTAL 2
XTAL 1
g
f
e
d
c
b
a a
b
c
d
e
f
g
a
b
c
d
e
f
g
a
b
c
d
e
f
g
g
f
e
d
c
dot
a
b
dot
LED2
LED1
LED3 LED4
LED1
LED2
LED3
LED4
SW1
SW2
SW4
SW3
GND
5V
SW1 SW2 5V
GND
SW3 5V
GND
SW4
5V
GND
SDA
SCL
SCL
SDA
5V
GND