infineon4engineers Facebook

infineon@google+ Google+

infineon@linkedin linkedin

infineon4engi@twitter twitter

infineon@youtube youtube

+ Reply to Thread
Results 1 to 3 of 3

Thread: XMC4800 how to modify SPI clk

  1. #1
    New Member New Member Janet is on a distinguished road
    Join Date
    Feb 2019
    Posts
    13
    Points
    145

    XMC4800 how to modify SPI clk

    Hi!
    I'm implementing an SPI daisy chain communication and i have some problem in sending and reading the 8th and 16th bit of the sent word. i'm usign the internal clk of my XMC4800 and since the first ISO chip is an output one, i set the clk as XMC_SPI_CH_BRG_SHIFT_CLOCK_PASSIVE_LEVEL_0_DELAY_D ISABLED.
    The problem is that the 8th and the 16th bit of the sent word aren't in the MISO, so i'd like to know if there's a way to forse the clk to stay high when i need it.

    I put a screenshot of the signals from the output ISO chip, the read one is the SCLK. In the MISO, don't look at the bit on the left, it's from an input ISO chip in daisy chain.

    Click image for larger version

Name:	Immagine.png
Views:	2
Size:	639.8 KB
ID:	3979

  2. #2
    New Member New Member Janet is on a distinguished road
    Join Date
    Feb 2019
    Posts
    13
    Points
    145
    I've changed the clock configuration to XMC_SPI_CH_BRG_SHIFT_CLOCK_PASSIVE_LEVEL_1_DELAY_D ISABLED, according to the reference manual of ISO1H812G.
    I have one 16bit ISO_out and one 16bit ISO_in in daisy chain configuration. The first 8 bits of the ISO_out are wired with the first 8bit of the ISO_in. I'm using ISO1I811T as input chip and ISO1H812G as output chip.
    Here there is a screenshot of what i get on the MOSI and MISO when i send 0xFF00 to the output chip.

    Click image for larger version

Name:	LeCroy.jpg
Views:	0
Size:	124.1 KB
ID:	3981

    Since the inputs and the outputs are wire connected, I expect to see the same value from the input and the output chips in the MISO, but the value of the input chip is right-shifted and had losted a bit. I think that is because of the clock configuration that is the one for the ISO1H812G and it doesn't work properly for the ISO1I811T .
    What I need is to change the clock configuration according to the chip is involved in the SPI communication, so i need to have the output clock configuration when the data is passing through ISO1H812G and the input clock configuration when the data is passing through ISO1I811T.
    If i change the clock configuration dynamically from the firmware code, it has no effect, the clock doesn't change. I've also tried to modify the clock setting the SCLK pin low when i need it, but in this way the outputs doesn't work properly.
    My question is: is there a proper way to switch between clock configuration? Or is there a way to generate a custom clock via software, avoinding the use of an external clock?

    Thank you for any help.

  3. #3
    New Member New Member Janet is on a distinguished road
    Join Date
    Feb 2019
    Posts
    13
    Points
    145
    Is there anyone who could help me with this SPI daisy chain problem?

+ Reply to Thread
Disclaimer

All content and materials on this site are provided “as is“. Infineon makes no warranties or representations with regard to this content and these materials of any kind, whether express or implied, including without limitation, warranties or representations of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, whether express or implied, is granted by Infineon. Use of the information on this site may require a license from a third party, or a license from Infineon.


Infineon accepts no liability for the content and materials on this site being accurate, complete or up- to-date or for the contents of external links. Infineon distances itself expressly from the contents of the linked pages, over the structure of which Infineon has no control.


Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Usage Terms of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Usage Terms of this site. Infineon reserves the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.