Dear Sirs,
I have new task in our design. In our design I have STM32F105VCT6 CPU. It has 4-line SPI interface. I want to connect SPI flash (S25FL128P0XNFI001) and microSD card with to our CPU, through this 4-line SPI interface simultaneously. MicroSD card will insert to MicroSD connector. Our device is control device; therefore bad customers will attempt to put out of operation it. For example, it can insert aluminum foil instead MicroSD card to connector. Our device must to continue to operate, i.e. 4-line SPI interface between CPU and SPI flash (S25FL128P0XNFI001) must to continue to operate. MicroSD card connector contains GND, SPI interface (4- lines) and 3.3 V power supply. I use same 3.3 V power supply for CPU too. I have two tasks:
1) I must make 3.3V power supply short circuit protection for MicroSD card connector.
2) I must make short circuit protection for SPI lines (MISO, MOSI, CLK, CS), because SPI interface between CPU and flash must to continue to operate. It may be buffer or other device. I must separate MicroSD connector signals and CPU SPI signals with the help of buffers or other devices. SPI clock is 10 - 20 MHz. (I have different CSs: CS0 for SPI flash, CS1 for microSD card. MISO, MOSI, CLK signals is common for CPU, SPI flash and microSD card).
Can I have TI chips for our tasks?
Best regards,
Ruslan Chaban, Russian, Perm, Fort-Telecom Inc, rchaban@fort-telecom.ru, design engineer, 13.12.2012
