From 8cd867cd53794386cb9443bfc023fe97c5c5fa47 Mon Sep 17 00:00:00 2001 From: Sadeep Madurange Date: Sat, 25 Oct 2025 18:19:48 +0800 Subject: Render posts. --- _site/archive/arduino-uno/3v3.Makefile | 46 ++++++++++++ _site/archive/arduino-uno/Makefile | 43 +++++++++++ _site/archive/arduino-uno/breadboard.jpeg | Bin 0 -> 54319 bytes _site/archive/arduino-uno/index.html | 117 ++++++++++++++++++++++++++++++ _site/archive/arduino-uno/pinout.png | Bin 0 -> 247197 bytes 5 files changed, 206 insertions(+) create mode 100644 _site/archive/arduino-uno/3v3.Makefile create mode 100644 _site/archive/arduino-uno/Makefile create mode 100644 _site/archive/arduino-uno/breadboard.jpeg create mode 100644 _site/archive/arduino-uno/index.html create mode 100644 _site/archive/arduino-uno/pinout.png (limited to '_site/archive/arduino-uno') diff --git a/_site/archive/arduino-uno/3v3.Makefile b/_site/archive/arduino-uno/3v3.Makefile new file mode 100644 index 0000000..4ca89d4 --- /dev/null +++ b/_site/archive/arduino-uno/3v3.Makefile @@ -0,0 +1,46 @@ +CC = avr-gcc +MCU = atmega328p +PORT = /dev/cuaU0 +TARGET = app + +SRC = main.c +OBJ = $(SRC:.c=.o) + +CFLAGS = -std=gnu99 +CFLAGS += -Os +CFLAGS += -Wall +CFLAGS += -mmcu=$(MCU) +CFLAGS += -DBAUD=57600 +CFLAGS += -DF_CPU=8000000UL +CFLAGS += -ffunction-sections -fdata-sections + +LDFLAGS = -mmcu=$(MCU) +LDFLAGS += -Wl,--gc-sections + +HEX_FLAGS = -O ihex +HEX_FLAGS += -j .text -j .data + +AVRDUDE_FLAGS = -p $(MCU) +AVRDUDE_FLAGS += -c arduino +AVRDUDE_FLAGS += -b 57600 +AVRDUDE_FLAGS += -P $(PORT) +AVRDUDE_FLAGS += -D -U + +%.o: %.c + $(CC) $(CFLAGS) -c -o $@ $< + +elf: $(OBJ) + $(CC) $(LDFLAGS) $(OBJ) -o $(TARGET).elf + +hex: elf + avr-objcopy $(HEX_FLAGS) $(TARGET).elf $(TARGET).hex + +upload: hex + avrdude $(AVRDUDE_FLAGS) flash:w:$(TARGET).hex:i + +.PHONY: clean + +clean: + rm -f *.o *.elf *.hex + + diff --git a/_site/archive/arduino-uno/Makefile b/_site/archive/arduino-uno/Makefile new file mode 100644 index 0000000..9db7b09 --- /dev/null +++ b/_site/archive/arduino-uno/Makefile @@ -0,0 +1,43 @@ +CC = avr-gcc +MCU = atmega328p +PORT = /dev/cuaU0 +TARGET = app + +SRC = main.c +OBJ = $(SRC:.c=.o) + +CFLAGS = -std=gnu99 +CFLAGS += -Os +CFLAGS += -Wall +CFLAGS += -mmcu=$(MCU) +CFLAGS += -DBAUD=115200 +CFLAGS += -DF_CPU=16000000UL +CFLAGS += -ffunction-sections -fdata-sections + +LDFLAGS = -mmcu=$(MCU) +LDFLAGS += -Wl,--gc-sections + +HEX_FLAGS = -O ihex +HEX_FLAGS += -j .text -j .data + +AVRDUDE_FLAGS = -p $(MCU) +AVRDUDE_FLAGS += -c arduino +AVRDUDE_FLAGS += -P $(PORT) +AVRDUDE_FLAGS += -D -U + +%.o: %.c + $(CC) $(CFLAGS) -c -o $@ $< + +elf: $(OBJ) + $(CC) $(LDFLAGS) $(OBJ) -o $(TARGET).elf + +hex: elf + avr-objcopy $(HEX_FLAGS) $(TARGET).elf $(TARGET).hex + +upload: hex + avrdude $(AVRDUDE_FLAGS) flash:w:$(TARGET).hex:i + +.PHONY: clean + +clean: + rm *.o *.elf *.hex diff --git a/_site/archive/arduino-uno/breadboard.jpeg b/_site/archive/arduino-uno/breadboard.jpeg new file mode 100644 index 0000000..bd74907 Binary files /dev/null and b/_site/archive/arduino-uno/breadboard.jpeg differ diff --git a/_site/archive/arduino-uno/index.html b/_site/archive/arduino-uno/index.html new file mode 100644 index 0000000..ff3ca44 --- /dev/null +++ b/_site/archive/arduino-uno/index.html @@ -0,0 +1,117 @@ + + + + + Notes on programming ATmega328P chips + + + Notes on programming ATmega328P chips + + + + + + + + + +
+ +
+ + + +
+
+

NOTES ON PROGRAMMING ATMEGA328P CHIPS

+ +
10 APRIL 2025
+ +
+ +

This post is a step-by-step guide for wiring up ATmega328P ICs to run at 5 V +with a 16 MHz crystal and 3.3 V with an 8 MHz crystal. While the 5 V +configuration is common, the 3.3 V configuration can be advantageous in +low-power applications and when interfacing with parts that run at 3.3 V.

+ +

5 V - 16 MHz configuration

+ +

The steps that follow refer to the following pinout.

+ + + + + + +
+ Pinout +

Pinout

+ 		+ Circuit +

Breadboard

+
+ +
    +
  1. Connect pin 1 to 5 V via a 10 kΩ resistor.
    2. +
  2. Connect a 16 MHz crystal oscillator across pins 9 and 10.
    3. +
  3. Connect each pin of the crystal to ground via 22 pF capacitors.
    4. +
  4. Connect pins 7, 20, and 21 to 5 V.
    5. +
  5. Connect pins 8 and 22 to ground.
    6. +
+ +

In addition to the connections described above, it’s a good idea to add 0.1 μF +decoupling capacitors between pins 7, 20, and 21 and ground. +Here’s a sample Makefile for avr-gcc and avrdude.

+ +

3.3 V - 8 MHz configuration

+ +

The following steps use Arduino Uno as an ISP and Arduino utilities to program +ATmega328P’s bootloader and the fuses (e.g., BOD level) for a 3.3 V supply.

+ +
    +
  1. Upload the ‘ArduinoISP’ sketch to the Uno.
    2. +
  2. Wire up the ATmega328P as described in the previous section. Replace the 5 V +supply with a 3.3 V supply and use an 8 MHz crystal instead of the 16 MHz +crystal.
    3. +
  3. Connect the SPI ports (SCK, MISO, and MOSI) of the two MCUs.
    4. +
  4. Connect Uno’s SS pin to the IC’s pin 1 (RESET).
    5. +
  5. The IC can be powered by the Arduino Uno’s 5 V pin.
    6. +
  6. Burn the bootloader to the ATmega328P: +
      +
    • Select ‘ATmega328P (3.3 V, 8 MHz)’ from Tools > Processor.
      • +
    • Select ‘Arduino as ISP’ from Tools > Programmer.
      • +
    • Select Tools > Burn Bootloader.
      • +
    +
    7. +
+ +

The ATmega328P is now ready to run at 8 MHz with a 3.3 V power supply. You can +upload programs to the ATmega328P as you usually would using avrdude. +Here’s a sample Makefile with adjusted parameters (e.g., baud +rate) for an 8 MHz clock.

+ +

In both configurations, if you intend to use the ATmega328P’s analog-to-digital +converter with the internal 1.1 V or AVcc voltage as reference, do +not connect AREF (pin 21) to Vcc. Refer to section 23.5.2 ADC +Voltage Reference in the datasheet for more information.

+ +
+ +

by W. D. Sadeep Madurange

+
+
+ + + diff --git a/_site/archive/arduino-uno/pinout.png b/_site/archive/arduino-uno/pinout.png new file mode 100644 index 0000000..59acfbc Binary files /dev/null and b/_site/archive/arduino-uno/pinout.png differ -- cgit v1.2.3