Diff: Cell_Voltage.cpp

Revision:

1:698bebac5005

Parent:

0:5163dda740af

Child:

2:04d9634b435b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Cell_Voltage.cpp	Mon Jun 19 11:59:23 2017 +0000
@@ -0,0 +1,114 @@
+#include "SPI_I2C_Parser.h"
+#include "mbed.h"
+#include "CAN_Data.h"
+#include "CAN_IDs.h"
+#include <stdlib.h>
+#include "Cell_Voltage.h"
+
+//Define SoC ALCC digital in pins might be necessary as a setup, testing needed
+//DigitalIn alcc(p20);
+//Timer t;
+
+/**
+* Sets the values of the cellvoltage array with units 100 uV from all of the CMUs
+* Uses the NO_CMUS parameter for the first dimension of cellcodes
+* @param cellcodes[NO_CMUS][12] Will hold the voltage values for every cell in uV.
+*/
+void LTC6804_acquireVoltage(uint16_t cellcodes [][12])
+{
+    //spi.format(8,3); //All data transfer on LTC6804 occur in byte groups. LTC6820 set up such that POL=1 and PHA=3, this corresponds to mode 3 in mbed library. spi.frequency(spiBitrate);
+    //spi.frequency(spiBitrate);
+     wake_LTC6804();//ensures CMU's are in ready state and wakes it up from low power mode
+     wait_us(330);
+     wake_LTC6804(); //This might need to be removed
+     LTC6804_acquireVoltageTx();
+     wait_us(930);
+     LTC6804_acquireAllVoltageRegRx(0, NO_CMUS, cellcodes);   
+}
+
+/**
+Sets the balancing transistors by adjusting the configuration states of the 
+LTC6804. This version of the function writes all 12 states for a chosen 
+transistor. If other forms end up being more useful I will add other overloaded
+versions.
+ 
+@param uint8_t ic The specific IC to write to (can be changed in favor of a 
+states array of size 12*total_ic if preferred)
+ 
+@param uint8_t states[12] For Sn in S1-S12 set states[n-1] to 1 to enable 
+balancing and 0 to disable balancing.
+*/
+void LTC6804_balance(uint8_t ic, uint8_t states[12])
+{
+        uint8_t total_ic = NO_CMUS;
+        //Consider using this to define the configs: (uint8_t *)malloc(total_ic*sizeof(uint8_t));
+        uint8_t r_config[total_ic][8];
+        uint8_t w_config[total_ic][6];//Size is smaller because there aren't PEC codes
+        wake_LTC6804();
+        wait_us(330);
+        LTC6804_rdcfg(total_ic, r_config); 
+        
+        /*for (int i=0; i<8; i++) {
+            printf("TEST %d config \r\n", (uint8_t)r_config[0][i]); 
+        } */
+        
+        uint8_t cfgr4 = 0; //This entire configuration is DCC states
+        uint8_t cfgr5 = r_config[ic][5];
+        
+        for(int i = 0; i < 8; i++)
+        {
+               //Note: This disgusting thing is written by someone who has not used c++ in a long time
+               cfgr4 = states[i] ? cfgr4 | (1u << i) : cfgr4 & ~(1u << i);
+        }
+        
+        for(int i = 8; i < 12; i++)
+        {
+               cfgr5 = states[i] ? cfgr5 | (1u << (i-8)) : cfgr5 & ~(1u << (i-8));
+        }
+        
+        //printf("cfgr4 %d \r\n", (uint8_t)cfgr4);
+        //printf("cfgr5 %d \r\n", (uint8_t)cfgr5);
+        for(int i =0 ; i < total_ic; i++)
+        {
+           for(int j = 0; j < 6; j++)
+            {
+                w_config[i][j] = r_config[i][j];   
+            }   
+        }
+        w_config[ic][4] = cfgr4;
+        w_config[ic][5] = cfgr5;
+        
+        wake_LTC6804();
+        wait_us(330);
+        LTC6804_wrcfg(total_ic,w_config); //Make sure this is written in the write order
+}
+/**
+Takes a set of voltages corresponding to cell voltage measurements and a voltage
+limit (presumably 4200 mV) and then drains all cells as needed. If current state
+of balancing is needed outside of this function, it can be modified.
+
+Current implementation of this function just uses the hard limit, so it might end
+up constantly enabling and disabling balancing as it hits the limit then goes under.
+That behavior can be improved upon if needed. One idea is to use derivative of
+voltage with time to predict when it will hit maxVoltage so there is no risk of 
+going over, or allow them to drain such that all of the cells are at the same voltage.
+
+@param uint16_t voltages[][12] Measured voltages to be used for deciding what to
+balance. The dimensions must be [total_ic][12].
+
+@param uint16_t maxVoltage voltage limit for the cells 
+*/
+void LTC6804_balanceVoltage(uint16_t voltages[][12], uint16_t maxVoltage)
+{
+        uint8_t total_ic = NO_CMUS;
+        //Consider making states a parameter as a pointer so it can be referenced outside of the function easier.
+        uint8_t states[total_ic][12];
+        for(int i = 0; i < total_ic; i++)
+        {
+            for(int j = 0; j < 12; j++)
+            {
+                states[i][j] = voltages[i][j] >= maxVoltage ? 1 : 0; //Not sure if ternary operator is needed in C.    
+            }
+            LTC6804_balance(i, states[i]);    
+        }
+}
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