Patching the TinyCard PCB
This page describes the changes needed to earlier TinyCard PCBs to update them to the latest version of TinyCard, Version 3.
For full information about TinyCard see the original article, TinyCard Game Maker.
Introduction
The latest version of the TinyCard PCB, Version 3, has been updated to add the additional decoupling capacitors C6 and C7 for reliable operation.
If you have earlier versions of the PCB you should add the capacitors by hand as described here:
The back of the TinyCard Version 1 PCB showing the two additional capacitors.
- Add C6, a 1µF ceramic capacitor, between the VDD and VSS pins on the SD card socket, as shown in the right-hand red circle above.
This solves a problem where inserting an SD card could cause a processor reset.
- Add C7, A 10µF ceramic capacitor, between pin 2 (IN) and pin 6 (GND) on the MAX619CSA SOIC-8 integrated circuit, as shown in the left-hand red circle above. Ensure that the two capacitor leads do not touch any other contacts.
This prevents switching noise that could cause incorrect reading of data from the keyboard, especially at lower power supply voltages.
After adding these components you could put a blob of silicone paste on each one to protect it; one suitable product is Chipquik EGS10C-20G clear Electronic Grade Silicone.
These capacitors have been incorporated into the Version 3 PCB as surface-mount components.
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