Implement current and voltage monitoring

[model-railway-devices.git] / arducontrol / arducontrol.c

diff --git a/arducontrol/arducontrol.c b/arducontrol/arducontrol.c
index 7b0c636b9ffb926ae811a9605a3b17e29806c633..d09fc09c3766e3dca9d41dbbd0125e250dae8c28 100644 (file)
--- a/arducontrol/arducontrol.c
+++ b/arducontrol/arducontrol.c
@@ -11,6 +11,10 @@ Connections for Pololu high-powered motor driver:
 D2 <-> DIR
 D3 <-> PWM
 
+ADC connections:
+ADC0 - current sensor (adjusted for 185 mV/A, centered at Vcc/2)
+ADC1 - input voltage (adjusted for divisor of 11)
+
 This is not a complete control device.  Rather, it is a low-level bus driver,
 intended to be controlled with a computer program.  In particular, no state is
 kept about locomotives or solenoids.  It is up to the controlling program to
@@ -30,6 +34,7 @@ blocks until the operation completes.  The command returns as soon as sending
 its data to the track can start.
 */
 #include <avr/io.h>
+#include "adc.h"
 #include "commands.h"
 #include "motorola.h"
 #include "packet.h"
@@ -50,6 +55,18 @@ volatile uint8_t recv_overrun = 0;
 uint8_t cmd_buf[15];
 uint8_t cmd_length;
 
+uint16_t track_current_samples[16] = { 0 };
+uint8_t track_current_head = 0;
+volatile uint16_t track_current_sum = 0;
+uint16_t overcurrent_limit = 1000<<4;
+uint8_t overcurrent_sent = 0;
+
+uint16_t input_voltage_samples[16] = { 0 };
+uint8_t input_voltage_head = 0;
+volatile uint16_t input_voltage_sum = 0;
+
+volatile uint8_t adc_state = 0;
+
 void process_commands();
 uint8_t process_command();
 
@@ -60,6 +77,7 @@ int main()
 
        serial_init(9600);
        timer_start_hz(0, 80000, 1);
+       adc_init();
 
        sei();
 
@@ -73,6 +91,23 @@ int main()
                }
                if(recv_fill>0)
                        process_commands();
+               if(!(adc_state&1))
+               {
+                       ++adc_state;
+                       adc_read_async(adc_state>>1);
+               }
+               if(track_current_sum>overcurrent_limit)
+               {
+                       PORTD &= ~0x08;
+                       if(!overcurrent_sent)
+                       {
+                               overcurrent_sent = 1;
+                               serial_write(0xFE);
+                               serial_write(OVERCURRENT);
+                       }
+               }
+               else
+                       overcurrent_sent = 0;
        }
 
        return 0;
@@ -152,6 +187,38 @@ uint8_t process_command()
                else
                        PORTD &= ~0x08;
        }
+       else if(cmd_buf[0]==READ_TRACK_CURRENT)
+       {
+               if(cmd_length!=1)
+                       return LENGTH_ERROR;
+
+               serial_write(0xFC);
+               serial_write(TRACK_CURRENT);
+               uint16_t value = track_current_sum>>4;
+               serial_write(value>>8);
+               serial_write(value);
+       }
+       else if(cmd_buf[0]==SET_OVERCURRENT_LIMIT)
+       {
+               if(cmd_length!=3)
+                       return LENGTH_ERROR;
+
+               if(cmd_buf[1]&0xF0)
+                       return INVALID_VALUE;
+
+               overcurrent_limit = (cmd_buf[1]<<12) | (cmd_buf[2]<<4);
+       }
+       else if(cmd_buf[0]==READ_INPUT_VOLTAGE)
+       {
+               if(cmd_length!=1)
+                       return LENGTH_ERROR;
+
+               serial_write(0xFC);
+               serial_write(INPUT_VOLTAGE);
+               uint16_t value = (input_voltage_sum>>3)*5;
+               serial_write(value>>8);
+               serial_write(value);
+       }
        else if(cmd_buf[0]==MOTOROLA_SPEED || cmd_buf[0]==MOTOROLA_SPEED_DIRECTION || cmd_buf[0]==MOTOROLA_SPEED_FUNCTION)
        {
                if(cmd_length!=4)
@@ -287,3 +354,41 @@ static inline void tick()
 }
 
 TIMER_SET_CALLBACK(0, tick)
+
+static inline void adc_complete(uint16_t value)
+{
+       if(adc_state==1)
+       {
+               // Convert to milliamps: (v*5/1024-2.5)*1000/0.185
+               if(value<512)  // Ignore negative current readings
+                       value = 0;
+               else if(value>663)  // Limit range so averaging won't overflow
+                       value = 4000;
+               else
+                       value = (value-512)*132/5;
+
+               uint8_t i = track_current_head;
+               track_current_sum -= track_current_samples[i];
+               track_current_samples[i] = value;
+               track_current_sum += value;
+               track_current_head = (i+1)&15;
+       }
+       else if(adc_state==3)
+       {
+               // Convert to centivolts: (v*5/1024)*100*11
+               if(value>744) // Limit range so averaging won't overflow
+                       value = 4000;
+               else
+                       value = value*43/8;
+
+               uint8_t i = input_voltage_head;
+               input_voltage_sum -= input_voltage_samples[i];
+               input_voltage_samples[i] = value;
+               input_voltage_sum += value;
+               input_voltage_head = (i+1)&15;
+       }
+
+       ++adc_state;
+}
+
+ADC_SET_CALLBACK(adc_complete)