2 layers99.1 × 49.9 mm
2 layers100 × 50 mm
Rc2014-ds1302-rtc
electrified/rc2014-ds1302-rtc25DS1302 Real Time Clock for the RC2014 computer
- Size
- 100 × 50 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 34
- Nets
- 63
- Pads
- 162
- Tracks, vias
- 205, 6
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 27 Jan 2018
- Updated
- 6 Jul 2025
Overview
Rc2014-ds1302-rtc is an open-source printed circuit board by electrified, from the electrified/rc2014-ds1302-rtc repository on GitHub. It is a 2-layer board of 100 × 50 mm with 34 parts on 63 nets, routed with 205 tracks and 6 vias.
It is built around the 74HCT125PW, 74HCT174D and 74HCT32D, with the 74HCT688D and DS1302+ among its other parts. Its parts include 5 capacitors, 5 ICs, 1 connector, 1 switch and 1 crystal. It belongs with the lEDs and displays boards of this library.
Main components
5
74HCT125PW
TSSOP-14-40℃~+125℃ 1 15ns@4.5V,50pF 160uA 4 4.5V~5.5V 6mA 6mA 74HCT Tri-State Unidirectional TSSOP-14 Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
74HCT174D
SO-16-40℃~+125℃ 1 3.5pF 35ns@4.5V,50pF 4.5V~5.5V 4mA 5.2mA 6 69MHz 74HCT Series 8uA D-Type Reset Rising Edge SO-16 Flip Flops ROHSNexperiaFlip Flops
74HCT32D
SO-14-40℃~+125℃ 2 24ns@4.5V,50pF 2V 2uA 3.7V、4.4V 4 4.5V~5.5V 400mV 4mA 4mA 74HCT Series 800mV OR Gate SOIC-14 Logic Gates ROHSNexperiaGates
74HCT688D
SOIC-20-300milSOIC-20-300mil Specialty Logic ROHSPhilips SemiconsSpecialty Logic
DS1302+
DIP-80℃~+70℃ 1nA 2V~5.5V 300nA Backup power management and battery charging、InsideSRAM/NVRAM External No SPI DIP-8 Real Time Clocks ROHSMaxim Integrated (Analog Devices)Real Time Clocks
README
README.mdDS1302 Real Time Clock for the RC2014 computer
The board
RomWBW has code to support a DS1302 Real Time Clock, enabling files to be timestamped and other timekeeping operations. This board implements the clock in a standard way for the RC2014.
The design is largely based on the clock implementation on the RetroBrew Computers SBC V2 and Zeta SBC V2.
What can you use this for?
Telling the time :)
Getting started with RomWBW
Set DSRTCENABLE to true in the configuration and rebuild your ROM image.
On startup you will see the time shown.
ZSystem has more complete support for time utilities than CP/M. After booting into ZSystem by pressing Z, Run ldds to load the resident time driver. td can then be used to set the time as well as view it.
In CP/M RTC.com can be used for querying and setting the clock but it is very basic.
Jumpers
SW1 - Address configuration. For the default address of 0xC0, set switches 5 and 6 to on.
Bill Of Materials
| Reference | Value | Farnell part no | Rapid part no | Digi-key part no |
|---|---|---|---|---|
| P1 | 1x39 right angled pin header | 732-5350-ND | ||
| BT1 | Keystone 106 20mm battery holder for CR2032 | 1650672 | 36-106-ND | |
| BT1 | CR2032 battery | P189-ND | ||
| U1 | CD74HCT688E COMPARATOR, SINGLE, PDIP-20 | 2407104 | 296-2131-5-ND | |
| U2 | SN74HCT125N LOGIC, BUS BUFF TRI-ST QD, 14DIP | 1739676 | 296-8386-5-ND | |
| U3 | CD74HCT174E 74HCT CMOS, 74HCT174, DIP16, 5.5V | 1105983 | 296-2100-5-ND | |
| U4 | DS1302N+ RTC W/ RAM, 248B, D-D-M-Y, HH:MM:SS, DIP | 2515367 | DS1302N+-ND | |
| U5 | SN74HCT32N IC, QUAD 2-INPUT OR, 74HCT32, DIP14 | 9591982 | 296-1615-5-ND | |
| C1-5 | 0.1uF MLCC capacitor | BC2665CT-ND | ||
| Y1 | 32.768 kHz crystal | 9712887 | 535-9034-ND | |
| RN1 | 10k 8 Pin Commoned Resistor Network | 63-0125 | 4608X-1-103LF-ND | |
| SW1 | 6 way DIL switch | 80-0338 | CT2066-ND | |
| U1 | CONN IC DIP SOCKET 20POS TIN | AE10015-ND | ||
| U2 | CONN IC DIP SOCKET 14POS TIN | AE10012-ND | ||
| U3 | CONN IC DIP SOCKET 16POS TIN | AE10013-ND | ||
| U4 | CONN IC DIP SOCKET 8POS TIN | AE10011-ND | ||
| U5 | CONN IC DIP SOCKET 14POS TIN | AE10012-ND |
Construction tips
The footprint for the battery holder is designed for a Keystone 106, other battery holders should work if the pins are ~20.5mm apart, which seems to be fairly standard.
Parts
34| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 0.1uF | Capacitor_THT:C_Disc_D3.0mm_W2.0mm_P2.50mm | C1, C2, C3, C4, C5 |
| 1 | 10K | Resistor_THT:R_Array_SIP8 | RN1 |
| 1 | 74HCT125 | Package_DIP:DIP-14_W7.62mm_Socket_LongPads | U2 |
| 1 | 74HCT174 | Package_DIP:DIP-16_W7.62mm_Socket_LongPads | U3 |
| 1 | 74HCT32 | Package_DIP:DIP-14_W7.62mm_Socket_LongPads | U5 |
| 1 | 74HCT688 | Package_DIP:DIP-20_W7.62mm_Socket_LongPads | U1 |
| 1 | Battery_Cell | Battery:BatteryHolder_Keystone_106_1x20mm | BT1 |
| 1 | Crystal | Crystal:Crystal_Round_D2.0mm_Vertical | Y1 |
| 1 | DS1302+ | Package_DIP:DIP-8_W7.62mm | U4 |
| 1 | LOGO | rc2014:clock | G*** |
| 1 | RC2014 BUS | rc2014:Pin_Header_Straight_1x39_Pitch2.54mm_NoSilk | P1 |
| 1 | SW_DIP_x06 | Button_Switch_THT:SW_DIP_SPSTx06_Slide_9.78x17.42mm_W7.62mm_P2.54mm | SW1 |
The 16 most common of 34 parts.
Questions
How big is the Rc2014-ds1302-rtc PCB?
It measures 100 × 50 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Rc2014-ds1302-rtc use?
34 parts, built around the 74HCT125PW, 74HCT174D, 74HCT32D and 74HCT688D. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Rc2014-ds1302-rtc KiCad files?
From the electrified/rc2014-ds1302-rtc repository on GitHub, at the commit this page was made from: the board is rc2014-ds1302-rtc.kicad_pcb and its schematic rc2014-ds1302-rtc.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Rc2014-ds1302-rtc design in my own project?
Its repository states no licence, so its author keeps all rights: ask electrified before reusing the design.
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