I am currently working on a RFID tag reader project. The reader is a product of Skyetek: M1-Mini with SPI protocol. I am using an Arduino based microcontroller that is SIMBLEE by RFDigital.
In order to make the reader work, every time I need to send a command consisting of several bytes of data, e.g. 0x02 0x06 0x20 0x22 0x01 0x0A. The returned message should look like 0x02 0x0C 0X14 0x0C 0X4D59.
The major function is spi.transfer() in the Simblee SPI libary. However, it sends 1 byte of data and reads back 1 byte of data every time. It may be ok to send the data by calling transfer() several times, e.g.
But how can the microprocessor read back the returned message? For different command, the number of bytes of the returned message is also different.
The microprocessor's SPI library doesn't have a transfer with buffer option.