Hi,
Can I make a connection between SSP0 and SSP1 interface of the same MCBSTR9 board?
I tried, but I have some problem with NSS signal of the slave interface.
Could you give me some advice?
Sory for my late responce. And thank you for your interest to my post. I learned a lot of things other then SPI, thank you for that aslo.
Getting back to my SPI problem, previously I was just waiting some starting point to SPI on MCBSTR9 board; example, article etc. (I think I was impatient, later I found some of them like http://www.keil.com/support/docs/3242.htm)
Actually there was no need to make connection between SSP0 and SSP1 interfaces of the same board. The master configuration of SPI interface looks very simple, however I wonder what is going on when I configure the SPI interface as slave. Because there is no device to make a master, I choose the MCBSTR9 as slave and master. Then I used GPIO3 for SSP1(slave) and GPIO5 for SSP0(master). Then, I connected the SSP1.NSS to the ground(continuously at low), and SSP0.NSS was idle. The frame format was TI frame format and clock freqency was 400 Khz. Continuously I tryied to send data from SSP0 to SSP1 but it did not work,there was no data on SSP1 recv buffer, however when I periodically touch and detach the SSP1.NSS signal to the ground, the SSP1 received some data.
The problem was that "how do I connect the NSS signal of both SSP1 and SSP0."
Thank you.
Note that the master normally have a slave select output pin, which you connect to the slave select pin of the slave.
In some situation, you use any GPIO pin on the master side to drive the slave select line of the slave. After all, a master may have multiple slaves that may need to be controlled individually to address which slave you currently wants to talk with.
While many better SPI controllers supports other protocols too, I haven't looked closer at the TI protocol. But at least for traditional SPI, you need to let the slave see a transition on the slave select signal to make sure that the slave is correctly synchronized with the data. A spurious noise bit on the clock signal will make the slave lose the bit synchronization and to be continuously out-of-sync until you either reset the SPI controller or toggles the slave-select signal off/on.