SC149 – Z80 CPU Module (RC2014)

SC149 is a Z80 CPU and clock module designed for the RC2014 bus.



KitsWebsiteShips from
Stephen C CousinsTindieUK
PCBsWebsiteShips from
Stephen C CousinsTindieUK
Assembled and TestedWebsiteShips from
Not available
See parts list

Parts List

KitSC149, v1.0, Kit – soon
PCB1SC149, v1.0, PCB
C1 and C22Capacitor, ceramic, 100 nF
C3 and C42Capacitor, ceramic, 22 pF
JP11Header, male, 2 row x 5 pin, straight
Jumper4Jumper shunt
P11Header, male, 1 row x 40 pin, angled
R11Resistor, 1M, 0.25W
R21Resistor, 1k, 0.25W
R3 to R75Resistor, 10k, 0.25W
U11Z80 CPU Z84C0008PEG, or
Z80 CPU Z84C0010PEG
U1 socket140-pin DIP socket
U2 socket114-pin DIP socket
X11Crystal, 7.3728MHz

Printed Circuit Board

User Guide

SC149 provides a Z80 Central Processing Unit (CPU) and a clock oscillator, typically 7.3728 MHz.

If you want to use this module without using the onboard clock oscillator, simply remove the 74HCT04 (U2).

Being a 40-pin standard bus module there are a few Z80 signals that are not available on the bus. These include /NMI, /BUSRQ, /BUSAK, and /WAIT. Most systems will not require these signals but if they are needed they are available on JP1. Either these signals can be connected to specific USER pins on the bus or can be connected with flying leads, such as a Dupont cables.

Input/output port functions
I/O Address ReadWrite
Jumper options
JP1User pin bus signals
JP1.1 connects USER4 to /NMI (NM)
JP1.2 connects USER3 to /BUSRQ
JP1.3 connects USER2 to /BUSAK
JP1.4 connects USER1 to /WAIT
JP1.5 connects USER4 to /BUSAK

4 – NM
3 – BR
2 – BA
1 – WA
4 – BA

It is recommended that jumper shunts not be fitted unless you have a specific need and have checked no other signals are connected to the same USER bus pins.

Assembly Guide

Below is the suggested order of assembly. A general guide to assembling circuit boards can be found here.

  • Resistors R1 to R7
    These can be fitted either way around
  • Sockets for U1 and U2
    Fit such that the notch in the socket matches the curve in the outline on the PCB silkscreen
  • Bus header P1
    Make sure the pins are parallel to the PCB so that the board is vertical when it is fitted into a backplane socket
  • Capacitors C1 to C4
    These can be fitted either way around
  • Crystal X1
    This can be fitted either way around
  • Header JP1
    Most systems will not need these so best left unconnected until needed
  • Insert the integrated circuits into their sockets
    Make sure the notch in the component is at the end indicated by the notch in the socket and the curve on the PCB silkscreen


  • This design is made in accordance with the “designed for RC2014” labelling scheme.
  • RC2014 is a trademark of RFC2795 Ltd.
  • This product is designed for hobby use and is not suitable for industrial, commercial, or safety-critical applications.
  • The product contains small parts and is not suitable for young children.

Homebrew 8-bit retro computing