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EMB1428Q: EMB1428Q,SPI

menglinwang
Prodigy 100 points
Part Number: EMB1428Q
Other Parts Discussed in Thread: ISO7241C, BQ76PL536EVM-3

HI

I have an application environment, 100 connection lithium batteries, the use of multiple EMB1428Q to do the matrix, how to isolate and operate the SPI, the use of CS too much, 3.3V, line 1 meter.
I tend to isolate the SPI with the use,  if TI has such a program.Recommend to me...

  • 0
    TI__Guru 54715 points

    Hi User,
    The SPI can be isolated using parts such as the ISO7241C. An example is used on the SPI of the bq76PL536EVM-3. It is shown on the TIDA-00821 schematic page 5, the PDF file presently has a problem but it can be found in the TIDA-00821 CAD Files download.

  • 0 in reply to WM5295
    Prodigy 100 points
    HI WM,
    If i use ISO7241C，How do I handle multiple paths CS？ Use digital isolators to isolate CS？ISO7241 only four 。5V signal on-line interference how to deal with?
  • 0 in reply to menglinwang
    TI__Guru 54715 points
    Hi User,
    It depends on how you do your design. The 100S battery would need at least 15 of the EMB1428 to cover the cells and could group them in at least 8 different voltage modules. You would need isolation to each voltage module at a different potential from your MCU. Your SPI bus design must be compatible. You could use multiple chip selects and enables from the MCU and send each to the separate isolators, or demultiplex CS signals to save pins on the MCU. You may be able to send control signals through the isolation boundary for demultiplexing on the module. In any case you will likely need more signals across the isolation boundary similar to the extra signals in TIDA-00821 which had a single SPI slave but additional signals. See the isolation options at www.ti.com/isolation.
    TIDA-00239 shows an example of separate SPI paths coming from a MCU, one or more paths could go through isolators. TIDA-00817 shows an example of decoding SPI to talk to different designs. In this case the isolation for the module came through an isolated interface to U1 which provides the SPI bus on that module. If you are providing SPI from a MCU peripheral you may need to multiplex CS rather than generating your own.
    Also note you will need to multiplex the MISO signals from the isolators back into the MCU, or use separate pins.