SieMo S50037 Data Book PRELIMINARILY
Reading from SieMo
Reading is similar to writing, in that an 8-bit read command (00000011) is sent first, followed by the address of the location to be read. The SieMo then outputs the 16-bit contents of the location on MISO during bits D[15:0] and a check-word during T[15:0].The check-word is composed of {command, address [15:8]}. The check-word may be used to 'sanity-check' a read operation to a memory location. This overcomes the problem encountered with typical serial peripheral interface slaves, whereby it is impossible to determine whether the data returned by a read operation is valid data, or the result of the slave device not responding.
figure 24 SPI read timing a
figure 25 SPI read timing b
Auto-Increment Operation
Sending a command word and the address of a register every time it is to be read or written can be a significant overhead, especially when large amounts of data are to be transferred. SieMo offers increased data transfer efficiency via its auto-increment operation. During operation, SieMo increments the address automatically. Only the data is transmitted or received over the serial peripheral interface bus. SieMo keeps the previous command word.
figure 26 Example Auto-Increment Operation
24/30
