SC604 – RCBus Compact Flash Module

SC604 is a Compact Flash module designed for the 40-pin RCBus.

Downloads

Errata

See notes about the Compact Flash adapter.

Suppliers

KitsWebsiteFromCurrency
Small Computers DirectSCDirectUKGBP
Stephen C CousinsTindieUKUSD
Small Computer CentralLectronzUKEuro/USD
PCBsWebsiteFromCurrency
Small Computers DirectSCDirectUKGBP
Stephen C CousinsTindieUKUSD
Small Computer CentralLectronzUKEuro/USD
Assembled and TestedWebsiteFromCurrency
Not available
Components
See parts list
Small Computers Direct does not collect VAT for EU countries
Tindie does not collect VAT for EU countries
Lectronz does collect EU VAT for orders up to 150 EUR

Parts List

ReferenceQtyComponent
PCB1SC604, v1.0, PCB
C1 to C44Capacitor, ceramic, 100 nF
C51Capacitor, electrolytic, 100 µF
LED11LED, green, 3mm, angled
P11Header, male, 1 row x 40 pin, angled
P21Header, male, 2 row x 20 pin, angled
P31Header, male, 1 row x 2 pin, angled
R1 to R33Resistor, 4k7, 0.25W
R41Resistor, 1k, 0.25W
Screw (for spacer)1Machine screw, 6mm, M3
Spacer1Spacer, 10mm, M3, nylon
U1174HCT138
U2174HCT32
U3174HCT74
IC socket 16-pin
U1
1Socket, DIP, 16-pin
IC socket 14-pin
U2 and U3
2Socket, DIP, 14-pin
Adapter1Compact Flash adapter
Component details and sourcing

Printed Circuit Board

User Guide

SC604 is a Compact Flash Card interface for RCBus. It uses Tadeusz Pycio’s design to correct the timing between the Z80 CPU and the Compact Flash card.

The LED indicates Compact Flash card activity, both read or write.

The Compact Flash card capacity is not critical, but it should be noted that plain CP/M 2.2 can only access the first 128MB of the card. RomWBW can access up to 2GB. Any space above these limits can not be accessed by the retro computer. High capacity, more modern, high speed cards are best avoided as they are more likely to cause noise issues on the bus.

Input/output port functions
I/O Address ReadWrite
0x10 to 0x17CF cardCF card
Jumper options
JumperFunction
none

Assembly Guide

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

See notes about the Compact Flash adapter.

  1. Resistors R1 to R4
    These can be fitted either way around
  2. 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
  3. Power header P3
  4. Decoupling capacitors C1, C2, C3 and C4
    These can be fitted either way around
  5. Sockets for U1, U2 and U3
    Fit such that the notch in the socket matches the curve in the outline on the PCB silkscreen
  6. Header pins P2
    Make sure the pins are parallel to the PCB so that the Compact Flash adapter board is vertical
    See notes about the Compact Flash adapter
  7. Light emitting diode LED1
    The angled LEDs in the kit only fit one way around, but standard LEDs need to have the short lead in the hole marked with a flat line, as described here
  8. Capacitor C5
    This must be fitted the correct way around, as described here
  9. 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
  10. Fit the nylon spacer in the mounting hole

Compatibility

This module conforms to the RCBus specification v1.0 for RCBus-2014 (40-pin bus) and RCBus-Z80 (40-pin bus).

The RCBus specification includes RCBus-2014 (both RC2014 standard 40-pin bus and RC2014 enhanced 60-pin bus) and also the full 80-pin RCBus. The 80-pin RCBus provides support for advanced Z80 features, such as the interrupt daisy-chain, as well as support for other processor families.

The table below indicates electrical compatibility with each backplane type (40, 60 and 80 pin)

Backplane?Compatibility notes
RCBus 80-pinFully supported
RCBus 60-pin
(RC2014 enhanced)
Fully supported
RCBus 40-pin
(RC2014 standard)
Fully supported

Notes

  • 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.
  • The Compact Flash interface circuit has been designed by Tadeusz Pycio and reproduced with his permission.

Homebrew 8-bit retro computing