problem in spi

[sreejith.s.s]

hai,

I have a misunderstanding in SPI_L_TO_H & SPI_XMIT_L_TO_H. I don't know what is the difference between these two. That is, what does the spi_ mean and also what does the spi_xmit_ mean.......... pls anyone help me.

[Ttelmah]

1) Use the Mode definitions instead:

[sreejith.s.s]

Hi
Mr. Ttelmah

It was very helpful to me, thank you very much. But I am still not having a good idea about the difference between the normal SPI_L_to_H
AND SPI_XMIT_L_TO_H and why these two are used in a same mode?

[ckielstra]

To configure SPI you always have to configure two settings:
1) Clock Polarity: The clock level when inactive
2) Clock Phase: At which clock edge the data is to be clocked in.

Freescale (Motorola) uses the names CPOL and CPHA.
For copyright reasons Microchip uses other names: CKP and CKE.
For unknown reasons CCS decided to use none of the above names and invented SPI_L_TO_H, SPI_H_TO_L and SPI_XMIT_L_TO_H.

Two configuration bits give a total of four combinations, for easier speaking often referred to as the four SPI-modes 0 to 3.

SPI parameter number 1 is easy to understand: Look at the clock level in inactive state, high or low, and that is your setting for CPOL/CKP/SPI_L_TO_H.

SPI parameter number 2 generates confusion because it is implemented in different ways:
- Freescale defines it as 'data is clocked in on the first edge (0) or second edge (1).
- Microchip defines it as 'data is clocked in on the first edge (1) or second edge (0).
- CCS defines it as 'data is clocked in on the positive edge (SPI_XMIT_L_TO_H) or negative edge (default)

In the table below you can see how all names relate to each other:

[sreejith.s.s]

Now its seems to be very clear for me thanks partners !