On my last post I mentioned about moving all code into PSoC4 and shrinking the board. So that is what I am doing. Moving all the code into the PSoC4 was fairly easy. Next step is to remove the use of Arduino shields, since they are easy to use but takes a lot of real state.

First I decided to cut down on the SD card shield space. For this tested out some circuitry for the SDCard. I put together a 74HC4050N hex buffer working as a level shifter from PSoC4 5v to SD 3.3 also I think is cleaner this way. This simple circuit allow to interface with the SDCard. To plug in the microSD I am using a microSD to SD adapter with a few pins soldered to it so it can be mounted into the bread board. That way I can stick the SD into the board but still take in and out the microSD without the need of a fancy adapter. For a proto-board though this should have a microSD adapter directly to the PCB, it is way smaller but if I do not have any available this will make the trick. For reference I used the Arduino wireless shield that has a microSD. The Arduino guys uses for their SD shield three small buffers instead of a full IC with 8 buffers. The SD protocol used here just need to pass through the level shifter MOSI, SCK and CS. The MISO goes straight from the SD to the PSoC since the PSoC supports very well the voltage from the SD the buffer is to protect the other way around. Meaning that the Hex buffers ends up using just three out of the six buffers the IC has. For a final board this is good since that alone can saves some space but makes it a little harder to solder, so it is a trade off.


Here is a pic of the SD circuit on a small bread board for testing.



For most of you guys holidays are over but in Puerto Rico they are not, so still I have family and friends gatherings that need to attend. I continue working on this as much as I can but family is family.

Using shields and stuff fully made from other is great (very fast) but when you can incorporate that into your boards layout is even better.