A memory card allows you to store data and transfer it from one computer to another. To make a memory card yourself, you need to buy a separate controller, a memory chip, a USB connector, a board from a radio store. You will also need capacitors, resistors, coils, and a crystal resonator.
It is necessary
- - bread board;
- - soldering iron;
- - memory chips and controller;
- - programmer;
- - programming environment.
Instructions
Step 1
Choose a controller for the memory chips you have. Pay attention to their interface. It is advisable to use a standard interface, if available. Otherwise, you will have to program it yourself. Remember that parallel transmission methods tend to have better performance than sequential ones. Use dedicated controllers that support USB. In addition, some controllers support the most common file systems in hardware.
Step 2
Think over the concept of the future memory card. Remember that the current consumption must be no more than 500 mA for USB1 and USB2. It is advisable to put a high-capacity filtering capacitor at the input of the device, so that in case of a power failure, it can write the file system. In this case, the charging current of the capacitor must be less than 500 mA.
Step 3
Build a breadboard to debug the future device. For this purpose, microcircuits in DIP packages are well suited, and for SMD components, special development boards with appropriate contact pads are produced. At this stage, it is better to choose a larger device for the convenience of further design edits.
Step 4
The next step is programming the controller. Now you have to breathe life into a set of chips, wires, boards and connectors. In addition to the standard functions of the memory card, you can equip it with possibilities limited only by your imagination. For example, enter information encryption, an indicator of the occupied space, backup to an additional microchip, and much more. Remember that without the protection bit set, the program memory of the controller can be easily read. If usually this only threatens with the loss of program code, then in the case of data encryption, all efforts to implement protection will be in vain.
Step 5
After debugging the software and hardware of the device, you can assemble the final version of the board with minimization of size, cost per device, and convenient location of indicators.
