From cbb3c9832bbe31d741930d43d3e21a04abeb12f8 Mon Sep 17 00:00:00 2001
From: VG <vg@devys.org>
Date: Wed, 28 Jan 2015 00:03:35 +0100
Subject: first commit

---
 .gitignore |  2 ++
 Makefile   | 35 +++++++++++++++++++++++++++++
 main.c     | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 readme.rst | 12 ++++++++++
 uart.h     | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 190 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 main.c
 create mode 100644 readme.rst
 create mode 100644 uart.h

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..597ad3c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+main.elf
+main.hex
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..22606ad
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,35 @@
+# settings for arduino nano v3
+DEVICE     = atmega328p
+CLOCK      = 16000000
+PORT=/dev/serial/by-id/usb-FTDI_FT232R_USB_UART_A9SBZLHD-if00-port0
+#AVRDUDE=avrdude -V -F -p m328p -c arduino -b 115200 -P$(PORT)
+#AVRDUDE=avrdude -p $(DEVICE) -c arduino -b 115200 -P $(PORT)
+AVRDUDE=avrdude -p $(DEVICE) -c arduino -b 57600 -P $(PORT)
+
+DEFS    = -DF_CPU=$(CLOCK)UL
+LIBS    = -Wl,--relax,--gc-sections,--print-gc-sections,--entry=main
+LIBS = -Wl,--entry=main,--gc-sections,--rela
+CFLAGS  = -Wall -Werror -pedantic -std=c99
+CFLAGS += -O2 -funsigned-bitfields -fpack-struct -fshort-enums
+CFLAGS += -mmcu=$(DEVICE) $(DEFS)
+#LDFLAGS = $(LIBS)
+
+all: main.hex size
+
+main.hex: main.c
+	avr-gcc -o main.elf $? $(CFLAGS) $(LDFLAGS)
+	avr-objcopy -j .text -j .data -O ihex main.elf main.hex
+
+f: flash
+flash: all
+	$(AVRDUDE) -U flash:w:main.hex:i
+
+clean:
+	rm -f *.o *.elf *.hex
+
+size:
+	avr-size --mcu=$(DEVICE) -t -A main.elf
+	avr-size --mcu=$(DEVICE) -C main.elf
+	avr-nm --size-sort main.elf
+
+
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..cd3cf6e
--- /dev/null
+++ b/main.c
@@ -0,0 +1,65 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "uart.h"
+
+#define SET_PWM(a) (OCR0A  = (a))
+
+void setup(void);
+
+int main(void)
+{
+    uint8_t output = 0, c;
+
+    setup();
+
+    for (;;) {
+        switch((c = uart_getchar())) {
+            case '?': break;
+            case 'n':
+            case '0': output  = 0; break;
+            case 'y':
+            case '1': output  = 1; break;
+            case 't':
+            case 'T': output ^= 1; break;
+        }
+
+        uart_putchar(c);
+
+        if (output)
+            SET_PWM(40);
+        else
+            SET_PWM(1);
+
+        _delay_ms(1000);
+        SET_PWM(0);
+    }
+
+    return 0;
+}
+
+void setup(void)
+{
+    /* serial */
+    uart_init();
+
+    /* Initialize timer for PWM
+     *** PWM with timer1 management:
+     * TCCR1A-COM1A1:
+     * TCCR1A-WGM10:
+     * TOP = 0x00FF
+     * frequency is : 12 MHz(fclk) / 256(prscl) / 255 (top)/ 2 = 91.91Hz
+     * frequency is : 18.432 MHz(fclk) / 256(prscl) / 255 (top)/ 2 = 141.18Hz
+     * frequency is : 18.432 MHz(fclk) / 1024(prscl) / 255 (top)/ 2 = 35.29Hz
+     * frequency is : 16 MHz(fclk) / 1024(prscl) / 255 (top)/ 2 = 30.64Hz
+     * TCCR1B CS12 = 256 prescaler, CS12 + CS10 = 1024 prescaler
+     *
+     * 23/24 =~ 1.5ms
+     */
+    TCCR0A |= _BV(COM1A1)  | _BV(WGM10);
+    TCCR0B |= _BV(CS12)    | _BV(CS10);
+    /* TIMSK0 |= _BV(TOIE0); */
+
+    /* pwm output; */
+    DDRD |= 0xFF;
+}
diff --git a/readme.rst b/readme.rst
new file mode 100644
index 0000000..4737ef5
--- /dev/null
+++ b/readme.rst
@@ -0,0 +1,12 @@
+Simple project to switch lights on/off with a servo (for fun)
+#############################################################
+
+This is a two night project to allow a little linux board to control the
+lights of the home. It does it by flapping a switch with a servo going from
+a position to another.
+
+Simple control is done on the serial line. Exemple with python:
+
+    import serial
+    s = serial.Serial('/dev/serial/device', baudrate=9600)
+    s.write(b't') # toggle switch
diff --git a/uart.h b/uart.h
new file mode 100644
index 0000000..22e0655
--- /dev/null
+++ b/uart.h
@@ -0,0 +1,76 @@
+/* #define F_CPU 16000000UL <= defined in Makefile */
+#define BAUD 9600
+
+/* This file is *highly* inspired from:
+ * http://www.appelsiini.net/2011/simple-usart-with-avr-libc
+ */
+
+#include <util/setbaud.h>
+
+#if 0
+static inline void uart_init()
+{
+    UCSRB |= (1 << RXEN)  | (1 << TXEN);
+    UCSRC |= (1 << UCSZ0) | (1 << UCSZ1);
+#define BAUD 115200
+#include <util/setbaud.h>
+    UBRRH = UBRRH_VALUE;
+    UBRRL = UBRRL_VALUE;
+#if USE_2X
+    UCSRA |= (1 << U2X);
+#else
+    UCSRA &= ~(1 << U2X);
+#endif
+}
+#endif
+
+void uart_init(void)
+{
+    UBRR0H = UBRRH_VALUE;
+    UBRR0L = UBRRL_VALUE;
+
+#if USE_2X
+    UCSR0A |= _BV(U2X0);
+#else
+    UCSR0A &= ~(_BV(U2X0));
+#endif
+
+    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); /* 8-bit data */
+    UCSR0B = _BV(RXEN0) | _BV(TXEN0);   /* Enable RX and TX */
+}
+
+void uart_putchar(char c)
+{
+    UDR0 = c;
+    loop_until_bit_is_set(UCSR0A, TXC0); /* Wait until transmission ready. */
+}
+
+char uart_getchar(void)
+{
+    loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
+    return UDR0;
+}
+
+#if 0
+/* alternatives for stream uses */
+void uart_putchar(char c, FILE *stream)
+{
+    if (c == '\n') {
+        uart_putchar('\r', stream);
+    }
+    loop_until_bit_is_set(UCSR0A, UDRE0);
+    UDR0 = c;
+}
+
+char uart_getchar(FILE *stream)
+{
+    loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
+    return UDR0;
+}
+#endif
+
+#if 0
+FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
+FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);
+FILE uart_io FDEV_SETUP_STREAM(uart_putchar, uart_getchar, _FDEV_SETUP_RW);
+#endif
-- 
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