Revision 0:6fed6c6c82b4, committed 2016-07-26

Comitter:

gvi70000

Date:

Tue Jul 26 10:49:57 2016 +0000

Commit message:

AD5235 - 1024-Position Digital Potentiometer

Changed in this revision

diff -r 000000000000 -r 6fed6c6c82b4 AD5235.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AD5235.cpp	Tue Jul 26 10:49:57 2016 +0000
@@ -0,0 +1,127 @@
+#include <mbed.h>
+#include "AD5235.h"
+ 
+AD5235::AD5235(SPI& _spi, PinName _cs) : spi(_spi), cs(_cs)
+{
+    spi.format(8,0);
+    spi.frequency(1000000);
+}
+ 
+
+//1 - Restore EEMEM (A0) contents to RDAC (A0) register. See Table 16.
+void AD5235::storeEEMEM2RDAC(uint8_t w)
+{
+    transferData(0x10 + w,  CMD_NOP);
+} 
+//2 - Store wiper setting. Store RDAC (A0) setting to EEMEM (A0). See Table 15. - Use a delay of 50ms!!!
+void AD5235::storeRDAC2EEMEM(uint8_t w)
+{
+    transferData(0x20 + w,  CMD_NOP);
+}
+//3 - Store contents of Serial Register Data Byte 0 and Serial Register Data Bytes 1 (total 16 bits) to EEMEM (ADDR). See Table 18.
+//Use a delay of 50ms!!!/RDAC1 is 0, RDAC2 is 1, User1 is 2....User13 is 14 
+void AD5235::setEEMEM(uint8_t w, uint16_t v)
+{
+    transferData(0x30 + w, v);
+} 
+//4 - Decrement by 6 dB. Right-shift contents of RDAC (A0) register, stop at all 0s.
+void AD5235::stepDown6Db(uint8_t w)
+{
+    transferData(0x40 + w,  CMD_NOP);
+} 
+//5 - Decrement all by 6 dB. Right-shift contents of all RDAC registers, stop at all 0s.
+void AD5235::stepDownAll6Db(void)
+{
+    transferData(0x50 , CMD_NOP);
+} 
+//6 - Decrement contents of RDAC (A0) by 1, stop at all 0s.
+void AD5235::stepDown1(uint8_t w)
+{
+    transferData(0x60 + w, CMD_NOP);
+} 
+//7 - Decrement contents of all RDAC registers by 1, stop at all 0s.
+void AD5235::stepDown1All(void)
+{
+    transferData(0x70, CMD_NOP);
+}
+//8 - Reset. Refresh all RDACs with their corresponding EEMEM previously stored values. - Use a delay of 30us!!!
+void AD5235::refreshAllRDAC(void)
+{
+    transferData(0x80, CMD_NOP);
+}
+//9 - Read contents of EEMEM (ADDR) from SDO output in the next frame. See Table 19. - Use a delay of 30us!!!
+uint16_t AD5235::getEEMEM(uint8_t w)
+{
+    transferData(0x90 + w, CMD_NOP);
+    wait_us(30);
+    return transferData(CMD_NOP, CMD_NOP);
+}
+//10 - Read RDAC wiper setting from SDO output in the next frame. See Table 20. - Use a delay of 30us!!!
+uint16_t AD5235::getWiper(uint8_t w)
+{
+    transferData(0xA0 + w, CMD_NOP);
+    wait_us(30);
+    return transferData(CMD_NOP, CMD_NOP);
+} 
+//11 - Write contents of Serial Register Data Byte 0 and Serial Register Data Byte 1 (total 10 bits) to RDAC (A0). See Table 14.
+void AD5235::setWiper(uint8_t w, uint16_t v)
+{
+    transferData(0xB0 + w, v);
+} 
+//12 - Increment by 6 dB: Left-shift contents of RDAC (A0),stop at all 1s. See Table 17.
+void stepUp6Db(uint8_t w)
+{
+    //transferData(0xC0, CMD_NOP);
+} 
+//13 - Increment all by 6 dB. Left-shift contents of all RDAC registers, stop at all 1s.
+void AD5235::stepUpAll6Db(void)
+{
+    transferData(0xD0, CMD_NOP);
+} 
+//14 - Increment contents of RDAC (A0) by 1, stop at all 1s. See Table 15.
+void AD5235::stepUp1(uint8_t w)
+{
+    transferData(0xE0 + w, CMD_NOP);
+}
+//15 - Increment contents of all RDAC registers by 1, stop at all 1s.
+ void AD5235::stepUp1All(void)
+ {
+    transferData(0xF0, CMD_NOP);
+}
+//16 - See page 21 in manual Another subtle feature of the AD5235 is that a subsequent CS strobe, without clock and data, repeats a previous command
+void AD5235::repeatCMD(void)
+{
+    cs = 0;
+    cs = 1;
+}
+
+float AD5235::getTolerance()
+{
+    float tol = getEEMEM(15);
+    int8_t b_1 = ((uint16_t)tol >> 8);
+    int8_t b_0 = ((uint16_t)tol & 0xFF);
+    if(b_1 > 127) //check if first bit in b_1 is 1
+        b_1 -= 128;
+    else
+        b_1 = -b_1;
+    for(uint8_t p = 0; p < 8; p++)
+    {
+        if((b_0 >> p) & 1)//check if but in position p is 1
+        {
+            tol =(float)b_1 + (float)b_0/ (float)(2 << p);//add the decimal part of the tolerance
+            break;
+        }
+    }
+    return tol;
+}
+
+uint16_t AD5235::transferData(uint8_t cmd, uint16_t val)
+{
+    uint8_t bytes[1];
+    cs = 0;
+    bytes[0] = spi.write(cmd);
+    bytes[0] = spi.write(val >> 8);
+    bytes[1] = spi.write(val & 0xFF);
+    cs = 1;
+    return (uint16_t)(bytes[0] << 8) + bytes[1];
+}
\ No newline at end of file

diff -r 000000000000 -r 6fed6c6c82b4 AD5235.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AD5235.h	Tue Jul 26 10:49:57 2016 +0000
@@ -0,0 +1,54 @@
+#ifndef AD5235_H
+#define AD5235_H
+ 
+#include "mbed.h"
+//Data Sheet http://www.analog.com/media/en/technical-documentation/data-sheets/AD5235.pdf
+
+//Control Registers
+#define CMD_NOP 0x00 //0- Do nothing
+    //EEMEM No.-Address-----EEMEM Content for …
+    //1         0000        RDAC1
+    //2         0001        RDAC2
+    //3         0010        USER1
+    //4         0011        USER2
+    //…         …           …
+    //15        1110        USER13
+    //16        1111        RAB1 tolerance
+
+    //Instruction 3 writes two data bytes (16 bits of data) to EEMEM.
+    //In the case of Address 0 and Address 1, only the last 10 bits
+    //are valid for wiper position setting.
+    //Basicaly it is CMD_USER2MEM + User mem address + user = B0011A3A2A1A0 + user
+    //  A3  A2  A1  A0  
+    //  0   0   0   0   RDAC1
+    //  0   0   0   1   RDAC2
+    //  1   1   1   1   Tolerance   Read Only
+
+class AD5235 {
+    SPI& spi;
+    DigitalOut cs;    
+public:
+    AD5235(SPI& _spi, PinName _cs);
+    void storeEEMEM2RDAC(uint8_t w);//1 - Restore EEMEM (A0) contents to RDAC (A0) register. See Table 16.
+    void storeRDAC2EEMEM(uint8_t w);//2 - Store wiper setting. Store RDAC (A0) setting to EEMEM (A0). See Table 15. - Use a delay of 50ms!!!
+    void setEEMEM(uint8_t w, uint16_t v);//3 - Store contents of Serial Register Data Byte 0 and Serial Register Data Bytes 1 (total 16 bits) to EEMEM (ADDR). See Table 18.- Use a delay of 50ms!!!/RDAC1 is 0, RDAC2 is 1, User1 is 2....User13 is 14
+    void stepDown6Db(uint8_t w);//4 - Decrement by 6 dB. Right-shift contents of RDAC (A0) register, stop at all 0s.
+    void stepDownAll6Db(void);//5 - Decrement all by 6 dB. Right-shift contents of all RDAC registers, stop at all 0s.
+    void stepDown1(uint8_t w);//6 - Decrement contents of RDAC (A0) by 1, stop at all 0s.
+    void stepDown1All(void);//7 - Decrement contents of all RDAC registers by 1, stop at all 0s.
+    void refreshAllRDAC(void);//8 - Reset. Refresh all RDACs with their corresponding EEMEM previously stored values. - Use a delay of 30us!!!
+    uint16_t getEEMEM(uint8_t w);//9 - Read contents of EEMEM (ADDR) from SDO output in the next frame. See Table 19. - Use a delay of 30us!!!
+    uint16_t getWiper(uint8_t w);//10 - Read RDAC wiper setting from SDO output in the next frame. See Table 20. - Use a delay of 30us!!!
+    void setWiper(uint8_t w, uint16_t v);//11 - Write contents of Serial Register Data Byte 0 and Serial Register Data Byte 1 (total 10 bits) to RDAC (A0). See Table 14.
+    void stepUp6Db(uint8_t w);//12 - Increment by 6 dB: Left-shift contents of RDAC (A0),stop at all 1s. See Table 17.
+    void stepUpAll6Db(void);//13 - Increment all by 6 dB. Left-shift contents of all RDAC registers, stop at all 1s.
+    void stepUp1(uint8_t w);//14 - Increment contents of RDAC (A0) by 1, stop at all 1s. See Table 15.
+    void stepUp1All(void);//15 - Increment contents of all RDAC registers by 1, stop at all 1s.
+    void repeatCMD(void);//16 - See page 21 in manual Another subtle feature of the AD5235 is that a subsequent CS strobe, withoutclock and data, repeats a previous command
+    float getTolerance(void);
+private:  
+uint16_t _reply;
+PinName _CS_pin;
+uint16_t transferData(uint8_t cmd, uint16_t val);
+};
+#endif
\ No newline at end of file