Diff: enc.cpp

Revision:

0:00c56a9c6dee

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/enc.cpp	Sat Mar 05 00:09:45 2016 +0000
@@ -0,0 +1,105 @@
+#include "enc.h"
+
+enc::enc(PinName mosi, PinName miso, PinName sck, PinName cs) : m_spi(mosi, miso, sck), csl(cs){
+    ushort zpos = 2228; // est. 8/6/2015 1773
+    ushort zhold;
+    m_spi.format(16, 1);
+    m_spi.frequency(50000);
+    csl=1;
+    wait(0.05);
+
+
+    write_spi(0x0019, 0); //SETTINGS2
+    write_spi(0x001D, 0);
+    write_spi(0x0018, 0); //SETTINGS1
+    write_spi(0x0018, 0);
+    
+    zhold = zpos >> 6; //8MSB of zero position
+    write_spi(0x0016, 0);
+    write_spi(zhold, 0);
+    
+    zhold = zpos & 0x003F; //6 LSB of zero position
+    write_spi(0x0017, 0);
+    write_spi(zhold, 0);   
+    
+    enc_pos.pos = 0;
+    enc_pos.oticks = 0;
+    enc_pos.offset = 0;
+    enc_pos.calibPos = 0;
+    }
+    
+enc::~enc(){
+ 
+}
+
+unsigned int enc::cal_state(){
+    return enc_pos.pos;
+}
+
+void enc::set_offset(){
+    enc_pos.offset = ams_read();
+}
+
+ushort enc::write_spi(ushort reg, u8 rw){
+    ushort data;
+    reg = reg | rw << 14;
+    reg = reg | par(reg);
+    csl=0;
+    data = m_spi.write(reg);
+    csl=1;
+    wait(0.00001);
+    return data;
+    
+}
+
+ushort enc::read_spi(ushort reg){
+    ushort data;
+    reg = reg | 1 << 14;
+    reg = reg | par(reg);
+    write_spi(reg, 1);
+    data = write_spi(0x0000, 1);
+    return data;  
+}
+
+/*!
+*****************************************************************************
+* Calculate even parity of a 16 bit unsigned integer
+*
+* This function is used by the SPI interface to calculate the even parity
+* of the data which will be sent via SPI to the encoder.
+*
+* \param[in] value : 16 bit unsigned integer whose parity shall be calculated
+*
+* \return : Even parity
+*
+*****************************************************************************
+*/
+ushort enc::par(ushort value)
+{
+    u8 cnt = 0;
+    u8 i;
+ 
+    for (i = 0; i < 16; i++)
+    {
+        if (value & 0x1)
+        {
+            cnt++;
+        }
+        value >>= 1;
+    }
+    cnt = cnt & 0x1;
+    return cnt << 15;
+}
+
+void enc::update_pos(){
+    enc_pos.pos = ams_read();
+}
+
+unsigned int enc::ams_read() {
+    unsigned int enc_data;
+
+    enc_data = read_spi(0x3FFE);
+    read_spi(0x0001);
+        
+    return enc_data & 0x3FFF;
+}
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