initial commits

R/rpi_spi_close.R

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+# rpi_spi_close
+
+#' Close the connection to an SPI device
+#'
+#' @param spiDeviceID an SPI device id as supplied by rpi_spi_open()
+#'
+#' @return
+#' @export
+#'
+#' @examples
+rpi_spi_close <- function(spiDeviceID) {
+  close(description = spiDeviceID)
+}

R/rpi_spi_open.R

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+# rpi_spi_open
+
+# good example
+# https://raspberry-projects.com/pi/programming-in-c/spi/using-the-spi-interface
+
+# spi_mode
+# https://www.analog.com/en/analog-dialogue/articles/introduction-to-spi-interface.html
+
+spiIncludes <- c("<fcntl.h>",
+                 "<unistd.h>",
+                 "<sys/ioctl.h>",
+                 "<linux/types.h>",
+                 "<linux/spi/spidev.h>"
+)
+
+#' Open a connection to a Raspberry Pi SPI device
+#'
+#' @param spiBus 0 or 1. Used as /dev/spidev[spiBus].[spiChan]
+#' @param spiChan 0 or 1. Used as /dev/spidev[spiBus].[spiChan]
+#' @param spiMode 0-3. Controls clock polarity & clock phase which defines logic low/high and rising/falling edge data sample
+#' @param spiBits Bits Per Word. Typically 8
+#' @param spiSpeed Transmission speed. 1000000 = 1MHz
+#'
+#' @return spiDeviceID which identifies the SPI device
+#' @export
+#'
+#' @examples
+rpi_spi_open <- function(spiBus, spiChan, spiMode, spiBits, spiSpeed) {
+  # we really ought to check these incoming values...
+
+  spiDevString <- paste0("/dev/spidev",spiBus,".",spiChan)
+  spiDeviceID <- file(description = spiDevString, open = "r+")
+
+  # set the write ioctl mode
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_WR_MODE,', spiMode)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  # set the read ioctl mode
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_RD_MODE,', spiMode)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  # set the spi write bitsPerWord
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_WR_BITS_PER_WORD,', spiBits)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  # set the spi read bitsPerWord
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_RD_BITS_PER_WORD,', spiBits)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  # set the spi write speed
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_WR_MAX_SPEED_HZ,', spiSpeed)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  # set the spi read speed
+  stringToEval <- paste0('ioctl(',spiDeviceID,', SPI_IOC_RD_MAX_SPEED_HZ,', spiSpeed)
+  evalCpp(stringToEval,
+          depends = spiIncludes)
+
+  return(spiDeviceID)
+}

R/rpi_spi_read.R

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+# rpi_spi_read

R/rpi_spi_readWrite.R

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+# rpi_spi_readWrite

R/rpi_spi_write.R

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+# rpi_spi_write