Merge pull request #31 from UnifiedEngineering/system-fan-control

Optional temperature-controlled system fan speed (transistor must be added, see systemfan.c)

src/io.c

@@ -67,7 +67,7 @@ void IO_Init(void) {
 	FIO0MASK = 0b01001101000000100000010001100000; // Mask out all unknown/unused pins
 	FIO1MASK = 0b11111111000000001111111111111111; // Only LCD D0-D7
 
-	FIO0DIR = 0b10000000011011000011101100000001; // Default output pins
+	FIO0DIR = 0b10000010011011000011101100000001; // Default output pins
 	FIO1DIR = 0b00000000000000000000000000000000;
 
 	FIO0PIN = 0x00; // Turn LED on and make PWM outputs active when in GPIO mode (to help 100% duty cycle issue)

src/main.c

@@ -35,6 +35,7 @@
 #include "nvstorage.h"
 #include "version.h"
 #include "max31855.h"
+#include "systemfan.h"
 
 extern uint8_t logobmp[];
 extern uint8_t stopbmp[];
@@ -195,6 +196,7 @@ int main(void) {
 	OneWire_Init();
 	SPI_TC_Init();
 	Reflow_Init();
+	SystemFan_Init();
 
 	Sched_SetWorkfunc( MAIN_WORK, Main_Work );
 	Sched_SetState( MAIN_WORK, 1, TICKS_SECS( 2 ) ); // Enable in 2 seconds

src/sched.h

@@ -20,12 +20,14 @@ typedef enum eTask {
 	SLEEP_WORK=0,
 	BUZZER_WORK,
 	KEYPAD_WORK,
+	SYSFANPWM_WORK,
 	MAIN_WORK,
 	ADC_WORK,
 	ONEWIRE_WORK,
 	SPI_TC_WORK,
 	UI_WORK,
 	REFLOW_WORK,
+	SYSFANSENSE_WORK,
 	NV_WORK,
 	SCHED_NUM_ITEMS // Last value
 } Task_t;

src/systemfan.c

@@ -0,0 +1,99 @@
+/*
+ * systemfan.c - Temperature controlled system fan handling for T-962 reflow controller
+ *
+ * Copyright (C) 2014 Werner Johansson, [email protected]
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This utilizes the (previously unused) ADO testpoint that is connected to
+ * GPIO0.25 to drive a N-ch/NPN transistor to control the (noisy) system fan.
+ *
+ * System fan connector pin 1 = GND, pin 2 = ~10VDC
+ *
+ * Disconnect fan from GND, connect this wire to transistor drain/collector. Also
+ * connect the anode of a catch diode here, cathode to pin 2 (~10VDC).
+ * Transistor source/emitter connects to ground, gate connects directly to ADO testpoint.
+ * If using a bipolar transistor connect base through a 4k7 resistor to ADO testpoint.
+ *
+ * Example transistors that works: 2N7000 (N-ch FET) or BC547B (bipolar NPN)
+ */
+
+#include "LPC214x.h"
+#include <stdint.h>
+#include <stdio.h>
+#include "systemfan.h"
+#include "sched.h"
+#include "reflow.h"
+
+#define SYSFAN_PWM_PERIOD (TICKS_MS( 10 ))
+
+uint32_t syspwmval = 0;
+
+static int32_t SystemFanPWM_Work( void ) {
+	static uint8_t state = 0;
+	int32_t retval;
+
+	if( state ) {
+		FIO0CLR = (syspwmval != SYSFAN_PWM_PERIOD) ? (1<<25) : 0; // SysFan off
+		retval = syspwmval ? (SYSFAN_PWM_PERIOD - syspwmval) : -1;
+	} else {
+		FIO0SET = syspwmval ? (1<<25) : 0; // SysFan on
+		retval = (syspwmval != SYSFAN_PWM_PERIOD) ? syspwmval : -1;
+	}
+	state ^= 1;
+	return retval;
+}
+
+static int32_t SystemFanSense_Work( void ) {
+	//static uint8_t lastsysfanspeed = 0;
+	uint8_t sysfanspeed = 0;
+
+	if( Reflow_IsTempSensorValid( TC_COLD_JUNCTION ) ) {
+		float systemp = Reflow_GetTempSensor( TC_COLD_JUNCTION );
+
+		// Sort this out with something better at some point
+		if( systemp > 50.0f ) {
+			sysfanspeed = 0xff;
+		} else if( systemp > 45.0f ) {
+			sysfanspeed = 0xc0;
+		} else if( systemp > 42.0f ) {
+			sysfanspeed = 0x80;
+		} else if( systemp > 40.0f ) {
+			sysfanspeed = 0x50;
+		}
+	} else {
+		sysfanspeed = 0xff; // No sensor, run at full speed as a precaution
+	}
+
+	uint32_t temp = SYSFAN_PWM_PERIOD >> 8;
+	temp *= sysfanspeed;
+	if( sysfanspeed == 0xff ) temp = SYSFAN_PWM_PERIOD; // Make sure we reach 100% duty cycle
+	syspwmval = temp;
+
+	Sched_SetState( SYSFANPWM_WORK, 2, 0 );
+	//lastsysfanspeed = sysfanspeed;
+	return TICKS_SECS( 5 );
+}
+
+void SystemFan_Init( void ) {
+	printf("\n%s",__FUNCTION__);
+	Sched_SetWorkfunc( SYSFANPWM_WORK, SystemFanPWM_Work );
+	Sched_SetWorkfunc( SYSFANSENSE_WORK, SystemFanSense_Work );
+
+	syspwmval = SYSFAN_PWM_PERIOD; // Turn on fan briefly at boot to indicate that it actually works
+	Sched_SetState( SYSFANPWM_WORK, 2, 0 ); // Enable PWM task
+	Sched_SetState( SYSFANSENSE_WORK, 1, TICKS_SECS( 2 ) ); // Enable Sense task
+}

src/systemfan.h

@@ -0,0 +1,6 @@
+#ifndef SYSTEMFAN_H_
+#define SYSTEMFAN_H_
+
+void SystemFan_Init( void );
+
+#endif /* SYSTEMFAN_H_ */

src/t962.h

@@ -33,7 +33,7 @@
  * 0.22 LCD RS output (0=cmd, 1=data)
  * 0.23 F1 button (active low, with pullup) VBUS input as alt function on LPC214x
  * 0.24 (No pin)
- * 0.25 AD0.4 accessible on test point marked ADO - DAC output as alt function
+ * 0.25 AD0.4 accessible on test point marked ADO - DAC output as alt function (now used for sysfan control)
  * 0.26 ? USB D+ on LPC214x-series of chips
  * 0.27 ? USB D- on LPC214x-series of chips
  * 0.28 Temperature sensor input 1 (AD0.1), this was the left-hand one in our oven