en:netzer:spi-master

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en:netzer:spi-master [2015/12/23 17:10] – [Communication] sveschen:netzer:spi-master [2025/06/11 20:42] (current) – external edit 127.0.0.1
Line 123: Line 123:
 | T | 0x54 | Wait 1\ ms till processing of the next character. | 1.5 | | T | 0x54 | Wait 1\ ms till processing of the next character. | 1.5 |
 | All others | Character is transparently transmitted. | | All others | Character is transparently transmitted. |
 +
 +
 +===== SPI master in single slave operation =====
 +
 +For using this SPI master in a single slave environment this example is provided here.
 +We assume that the slave is connected with the SPI_CS wire like shown below.
 +
 +{{:en:netzer:spi_master_connection.gif|}}
 +
 +The SPI_CS shall be low active - a low level selects the slave.
 +The pull up resistor at CS is needed to prevent false selection.
 +This may occur on power up if CS is not driven by Netzer.
 +The pull up resistor at SPI_MI is needed to prevent floating in case the slave is not selected and therefore the pin is not driven.
 +
 +The data string <code>01 23 45 67 89</code> shall be sent to the SPI slave.
 +
 +The command for controlling the SPI_CS line is an escape sequence consisting of two bytes:
 +<code>5c 69</code> for setting SPI_CS to low and
 +<code>5c 49</code> for setting SPI_CS to high.
 +
 +The final code together:
 +<code>5c 69 01 23 45 67 89 5c 49</code>