Diff: libraries/ad5270/AD5270.cpp

Revision:

1:c1f0670bb370

Child:

3:1a8c14043a4e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libraries/ad5270/AD5270.cpp	Wed Mar 30 17:35:04 2016 +0300
@@ -0,0 +1,94 @@
+/**
+*   @file     AD5270.cpp
+*   @brief    Source file for AD5270 rheostat
+*   @version  V0.1
+*   @author   ADI
+*   @date     March 2015
+**/
+
+#include "mbed.h"
+#include "AD5270.h"
+
+/**
+ * @brief AD5270 constructor, sets CS pin and SPI format
+ * @param CS - (optional)chip select of the AD5270
+ * @param max_resistance - (optional) nominal resistance of the AD5270 chip in ohms
+ * @param MOSI - (optional)pin of the SPI interface
+ * @param MISO - (optional)pin of the SPI interface
+ * @param SCK  - (optional)pin of the SPI interface
+ */
+AD5270::AD5270(PinName CS, float max_resistance, PinName MOSI,PinName MISO,PinName SCK):
+    ad5270(MOSI,MISO,SCK),cs(CS),_max_resistance(max_resistance)
+{
+    ad5270.format(8,3);
+    cs=true;
+}
+
+/**
+ * @brief Compute for the nearest RDAC value from given resistance
+ * @param resistance - resistor
+ * @return RDAC value - closest possible to given resistance
+ */
+uint16_t AD5270::calc_RDAC(float resistance)
+{
+    return static_cast<uint16_t>( (resistance / _max_resistance) * 1024.0 );
+}
+
+/**
+ *	@brief Puts the AD5270 SDO line in to Hi-Z mode
+ *	@return none
+ */
+void AD5270::set_SDO_HiZ(void)
+{
+    write_reg(HI_Z_Cmd);
+    write_reg(NO_OP_cmd);
+}
+
+/**
+ * @brief Set AD5270 SPI frequency
+ * @param hz - SPI bus frequency in hz
+ * @return none
+ */
+void AD5270::frequency(int hz)
+{
+    ad5270.frequency(hz);
+}
+
+/**
+ * @brief Issues AD5270 a command
+ * @param command - command to be sent
+ * @param data - (optional)value for the requested command
+ * @return response form the AD5270
+ */
+uint16_t AD5270::write_cmd(uint8_t command, uint16_t data)
+{
+    /* build 16 bit data to be written - Command + Value */
+    uint16_t ui16Command = ((command & 0x3C) << 8) | (data & 0x3FF);
+    return write_reg(ui16Command);
+}
+
+/**
+ * @brief Writes 16bit data to the AD5270 SPI interface
+ * @param data to be written
+ * @return data returned by the AD5270
+ */
+uint16_t AD5270::write_reg(uint16_t data)
+{
+    uint16_t result;
+    uint8_t upper_byte = (data >> 8) & 0xFF;
+    uint8_t lower_byte =  data & 0xFF;
+    cs = false;
+    result  = ((ad5270.write(upper_byte)) << 8);
+    result |=   ad5270.write(lower_byte);
+    cs = true;
+    return result;
+}
+
+/**
+ * @brief Gets maximum resistance of the AD5270 digital rheostat
+ * @return maximum resistance in ohms
+ */
+float AD5270::get_max_resistance()
+{
+    return _max_resistance;
+}