Also for identical devices, separate SPI interfaces are important in case of different drivers. For example, think of copying from a QLWA formatted SDHC card to a Quibide formatted card, if one driver is built into SMSQ/E and the other one is separate. This is one reason why the Q68 has separate interfaces for both card sockets. Of course it also increases copying speed.Nasta wrote:it is possible to use a single SPI interface with multiple devices, it becomes more and more difficult if the devices are very different.
Then the Q68 will disappoint you here. I did not have enough FPGA pins for more than RX and TX. Also I didn't want to use one of the bloated existing UART IP cores, so I went for a simple, efficient implementation with 16 Bytes FIFO. My thought was: Better no handshake at all ,than a not 100% reliable handshake. On the positive side, the Q68 RS-232 transceiver is one of the few, which truly support 460kbps.Nasta wrote:I cannot over-emphasize the importance of hardware handshaking.
I also believed that, until I really tried. I found very few >460 kbps rated adaptors capable of true 230kbps. Try transfering continuos long streams, even with hardware handshake, and you will see.Nasta wrote:Final note - most USB to serial adapters are capable of a few high bit rates, [...]