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CF-card interface

A project log for Thunderbird-yet another 68000 SBC

An easy-to-build and easy-to-understand single-board retro computer, perfect for overclocking and running the Fuzix OS!

stevenSteven 03/02/2025 at 15:380 Comments

Introduction

In homebrew retro computing, the CompactFlash (CF) card is very popular, but SD cards are also used. In Thunderbird, both can be used.

CF/IDE-interface (44 pin)


SD-card (SPI)

SD-to-IDE interface (44 pin)

On the internet, there are inexpensive ($10) SD-to-IDE converters. These tiny boards accept either a full-size or microSD card and feature a 44-pin IDE interface. This fits perfectly into the Thunderbird design! I tested it on the board, and it worked flawlessly. The interface supports both 16-bit and 8-bit modes, with the latter being ideal for Z80 or 6502 designs.

Micro SD to 2.5 44pin IDE Adapter Reader TF CARD to ide For Laptop -  Newegg.com

CF-card
(44 pin)
SD to IDE interface (44 pin)SD-card
(with interface)
Voltage:5 V5 V3.3 V (5 V with interface)
Total system power (@20MHz):200 mA190 mA?? mA
Interface:8/16 bits to databus8/16 bits to databusSPI ("bit bang")
Read (sequential):700 KB/s800 KB/s10~25 KB/s (educated guess)
Read (random):525 KB/s550 KB/s10~25 KB/s (educated guess)


Conclusion

For me, the SD-to-IDE interface is a winner. Although there is a slight speed difference between the CF card and the SD-to-IDE interface, their speeds are approximately the same. However, since SD cards are more common, I prefer the SD-to-IDE interface.

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