Diff: mcp23s17.h

Revision:

0:fa7450a43b99

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mcp23s17.h	Mon Dec 04 09:32:20 2017 +0000
@@ -0,0 +1,97 @@
+//
+// Filename: mcp23s17.h
+//
+// Flexbook Hardware Abstraction Layer.
+//
+
+#ifndef MCP23S17_H
+#define MCP23S17_H
+
+#include "mbed.h"
+
+namespace HAL {
+
+/**
+ * @brief MCP23S17 register addresses in bank 0 mode.
+ */
+enum REG_MCP23S17
+{
+IODIRA   = 0x00,
+IODIRB   = 0x01,
+IPOLA    = 0x02,
+IPOLB    = 0x03,
+GPINTENA = 0x04,
+GPINTENB = 0x05,
+DEFVALA  = 0x06,
+DEFVALB  = 0x07,
+INTCONA  = 0x08,
+INTCONB  = 0x09,
+IOCON1   = 0x0a,
+IOCON2   = 0x0b,
+GPPUA    = 0x0c,
+GPPUB    = 0x0d,
+INTFA    = 0x0e,
+INTFB    = 0x0f,
+INTCAPA  = 0x10,
+INTCAPB  = 0x11,
+GPIOA    = 0x12,
+GPIOB    = 0x13,
+OLATA    = 0x14,
+OLATB    = 0x15
+};
+
+/**
+ * @brief Microchip MCP23S17 encapsulation.
+ * This chip is an SPI connected I/O expander.
+ *
+ * Example usage:
+ <pre>
+    SPI spi(p5, p6, p7);
+    DigitalOut cs(p19);
+    MCP23S17 mcp23s17(0x00, spi, cs);
+    ...
+    mcp23s17.Write(GPIOB, 0xaa);
+ </pre>
+ *
+ * The MCP23S17 uses pins 5, 6, 7 (SPI MOSI, MISO, SCK) and 19 (CS) and
+ * the write command sets GPIOB to 0xaa. The chip address is 0x00.
+ *
+ * Note that this code example does not cover the setup of the chip
+ * configuration registers.
+ */
+class MCP23S17
+{
+public:
+    /**
+     * @brief Constructor.
+     * @param address The SPI address offset of the chip.
+     * @param SPI the SPI to use for communication.
+     * @param cs The chip select pin.
+     */
+    MCP23S17(int address, SPI &spi, DigitalOut &cs);
+
+    /**
+     * @brief Read a register.
+     * @param address The SPI address of the MCP23S17.
+     * @param reg The register to read.
+     * @return The register value.
+     */
+    int Read(REG_MCP23S17 reg);
+
+    /**
+     * @brief Write a register.
+     * @param address The SPI address of the MCP23S17.
+     * @param reg The register to write.
+     * @param value The value to write to the register.
+     */
+    void Write(REG_MCP23S17 reg, int value);
+
+private:
+    int address;
+    SPI &spi;
+    DigitalOut &cs;
+};
+
+} // End HAL namespace.
+
+#endif // MCP23S17_H