PD1-C Modbus RTU Online Manual

Generic SPI

The controller can communicate with external devices via this SPI interface, e.g. port expanders or displays. The corresponding pins are only available with product variants PD1-…-OF-….

Note: The used SPI peripheral must support a clock frequency of at least 164 KHz.

The settings of the SPI interface are located in object 3273h:01h (Generic SPI Hardware Configuration):

  • Bit 0 (Clock Phase):
    • Value = "0": Data transfer begins with the first clock edge after Chip Select was pulled to low.
    • Value = "1": Data transfer begins with the second clock edge after Chip Select was pulled to low.
  • Bit 1 (Clock Polarity): With this bit, you can invert the polarity of the clock signal. The value 0 means the level remains on Low if the clock is idling.
  • Bits 2 to 4 (baud rate): You set the clock frequency here:
    • 000b: 21 MHz
    • 001b: 10.5 MHz
    • 010b: 5.25 MHz
    • 011b: 2625 KHz
    • 100b: 1312.5 KHz
    • 101b: 656.25 KHz
    • 110b: 328.125 KHz
    • 111b: 164.0625 KHz
  • Bit 10 (CS Polarity): With this bit, you can invert the polarity of the Chip Select. Value 0 means that the level remains on High if the signal is idling.

 

The data are sent/received via the following objects:

  • 3274h (Generic SPI Mosi Data):
    • Subindex 1 to 1Fh (Generic SPI Mosi Data Byte #1 to #31): You write the data that are to be sent here, divided into up to 31 bytes.
    • Subindex 0 (Length of SPI message to be sent): Then enter the number of bytes here (= subindicies) that are to be sent. In the next millisecond cycle, the data are sent and the subindex is reset to the value "0".
  • 3275h (Generic SPI Miso Data): You read the received data here.
    • Subindex 0 (Length of received SPI message): The value tells you how many data bytes (= subindices) were received.
    • Subindex 1 to 1Fh (Generic SPI Miso Data Byte #1 to #31): The data that were received are located here.
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