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boards/atmega8: new board

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This commit is contained in:
Hugues Larrive 2023-06-22 11:25:38 +02:00
parent 064c799e57
commit e8327a4a9a
9 changed files with 285 additions and 3 deletions
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25
boards/atmega8/Kconfig Normal file
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# Copyright (c) 2020 HAW Hamburg
#
# This file is subject to the terms and conditions of the GNU Lesser
# General Public License v2.1. See the file LICENSE in the top level
# directory for more details.
config BOARD
default "atmega8" if BOARD_ATMEGA8
config BOARD_ATMEGA8
bool
default y
select CPU_MODEL_ATMEGA8
# Put defined MCU peripherals here (in alphabetical order)
select HAS_PERIPH_ADC
select HAS_PERIPH_GPIO
select HAS_PERIPH_I2C
select HAS_PERIPH_PWM
select HAS_PERIPH_SPI
select HAS_PERIPH_TIMER
select HAS_PERIPH_UART
# Various other features (if any)
select MODULE_BOARDS_COMMON_ATMEGA if TEST_KCONFIG
source "$(RIOTBOARD)/common/atmega/Kconfig"

5
boards/atmega8/Makefile Normal file
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MODULE = board
DIRS = $(RIOTBOARD)/common/atmega
include $(RIOTBASE)/Makefile.base

1
boards/atmega8/Makefile.dep Normal file
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USEMODULE += boards_common_atmega

9
boards/atmega8/Makefile.features Normal file
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CPU = atmega8
FEATURES_PROVIDED += periph_adc
FEATURES_PROVIDED += periph_gpio
FEATURES_PROVIDED += periph_i2c
FEATURES_PROVIDED += periph_pwm
FEATURES_PROVIDED += periph_spi
FEATURES_PROVIDED += periph_timer
FEATURES_PROVIDED += periph_uart

16
boards/atmega8/Makefile.include Normal file
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# configure the terminal program
PORT_LINUX ?= /dev/ttyUSB0
PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
BAUD ?= 9600
ATMEGA8_CLOCK ?=
# Allow overwriting programmer via env variables without affecting other boards
PROGRAMMER_BOARD_ATMEGA8 ?= usbasp
# ICSP programmer to use for avrdude
AVRDUDE_PROGRAMMER ?= $(PROGRAMMER_BOARD_ATMEGA8)
ifneq (,$(ATMEGA8_CLOCK))
CFLAGS += -DCLOCK_CORECLOCK=$(ATMEGA8_CLOCK)
endif
include $(RIOTBOARD)/common/atmega/Makefile.include

99
boards/atmega8/doc.txt Normal file
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/**
@defgroup boards_atmega8 Standalone ATmega8
@ingroup boards
@brief Support for using the ATmega8 as standalone board
## Overview
As the ATmega8 can run from the internal oscillator, placing it on a breadboard,
connecting an USB-UART adapter and power is enough to run RIOT on it. (An ISP
programmer will be needed to program it; or to program a bootloader to
subsequently allow programming via UART.)
### MCU
| MCU | ATmega8 |
|:------------- |:--------------------------------------------- |
| Family | AVR/ATmega |
| Vendor | Microchip (previously Atmel) |
| RAM | 1KiB |
| Flash | 8KiB |
| EEPROM | 512B |
| Frequency | 1MHz/8MHz (up to 16MHz with external clock) |
| Timers | 3 (2x 8bit, 1x 16bit) |
| ADCs | 6 analog input pins |
| UARTs | 1 |
| SPIs | 1 |
| I2Cs | 1 (called TWI) |
| Vcc | 4.5V - 5.5V (ATmega8), 2.7V - 5.5V (ATmega8L) |
| Datasheet | [Official datasheet](https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-2486-8-bit-AVR-microcontroller-ATmega8_L_datasheet.pdf) |
### Pinout
\htmlonly<style>div.image img[src="https://camo.githubusercontent.com/c55beef2f138da61fe671a1e4a307ff4ffbc318d/68747470733a2f2f692e696d6775722e636f6d2f715849456368542e6a7067"]{width:100%;}</style>\endhtmlonly
@image html "https://camo.githubusercontent.com/c55beef2f138da61fe671a1e4a307ff4ffbc318d/68747470733a2f2f692e696d6775722e636f6d2f715849456368542e6a7067" "Pinout of the ATmega328p"<br>
All credit for above pinout image goes to https://github.com/MCUdude/MiniCore#pinout
### Clock Frequency
The ATmega8 has an internal oscillators clocked at 1MHz that allow it to be
operated without any external clock source or crystal. By default the fuses are
configured to use the internal oscillator and an operating mode resulting in a
clock speed of 1MHz. By setting the `CKSEL` fuses to 0100 the clock will operate
at 8MHz without an external clock source. This can be done like this:
avrdude -c usbasp -p m8 -B 32 -U lfuse:w:0xe4:m
(Replace `usbasp` with the ISP programmer you are using. The `-B 32` might
be needed on some ISP programmers to communicate with slow ATmega MCUs. It will
not be needed anymore after the clock device has been disabled.)
This "board" is configured to use 8MHz as core clock, so that the ATmega8
runs at the highest frequency possible without external clock sources.
By setting the environment variable `ATMEGA8_CLOCK` to a custom frequency in
Hz (e.g. `1000000` for 1MHz), this core clock can be changed easily. Refer to
the datasheet on how to configure the ATmega8 to use an external crystal, an
external clock source or the clock divider.
### Relation Between Supply Voltage, Clock Frequency and Power Consumption
A higher supply voltage results in a higher current drawn. Thus, lower power
consumption can be achieved by using a lower supply voltage. However, higher
clock frequencies require higher supply voltages for reliable operation.
The lowest possible supply voltage at 8 MHz is 2.7V (Atmega8L) or
4.5V (Atmega8).
## Flashing the Device
In order to flash the ATmega8 without a bootloader, an ISP programmer is
needed. Connect the programmer as follows:
| ISP pin | ATmega8 pin |
|:-------- |:-------------- |
| MISO | 18/PB4/MISO |
| VCC | 7/VCC |
| SCK | 19/PB5/SCK |
| MOSI | 17/PB3/MOSI |
| RESET | 1/RESET |
| Ground | 22/GND |
The tool `avrdude` needs to be installed. When using the `usbasp` running
make BOARD=atmega8 flash
will take care of everything. To use the programmer `<FOOBAR>` instead, run
make BOARD=atmega8 PROGRAMMER=<FOOBAR> flash
## Serial Terminal
Connect a TTL adapter with pins 2/RXD and 3/TXD an run
make BOARD=atmega8 term
Please note that the supply voltage should be compatible with the logic level of
the TTL adapter. Usually everything between 3.3 V and 5 V should work.
*/

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boards/atmega8/include/board.h Normal file
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/*
* Copyright (C) 2014 Freie Universität Berlin, Hinnerk van Bruinehsen
* 2016 Laurent Navet <laurent.navet@gmail.com>
* 2019 Otto-von-Guericke-Universität Magdeburg
* 2023 Hugues Larrive
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup boards_atmega8
* @{
*
* @file
* @brief Board specific definitions for the standalone ATmega8 "board"
*
* @author Marian Buschsieweke <marian.buschsieweke@ovgu.de>
* @author Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
* @author Laurent Navet <laurent.navet@gmail.com>
* @author Hugues Larrive <hugues.larrive@pm.me>
*/
#ifndef BOARD_H
#define BOARD_H
#include "cpu.h"
#include "periph_conf.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name STDIO configuration
*
* As the CPU is too slow to handle 115200 baud, we set the default
* baudrate to 9600 for this board
* @{
*/
#define STDIO_UART_BAUDRATE (9600U)
/** @} */
/**
* @name xtimer configuration values
* @{
*/
#define XTIMER_WIDTH (16)
#if CLOCK_CORECLOCK > 4000000UL
#define XTIMER_HZ (CLOCK_CORECLOCK / 64)
#else
#define XTIMER_HZ (CLOCK_CORECLOCK / 8)
#endif
#define XTIMER_BACKOFF (40)
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* BOARD_H */
/** @} */

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boards/atmega8/include/periph_conf.h Normal file
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/*
* Copyright (C) 2019 Otto-von-Guericke-Universität Magdeburg
* 2023 Hugues Larrive
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup boards_atmega8
* @{
*
* @file
* @brief Peripheral MCU configuration for the ATmega8 standalone "board"
*
* @author Marian Buschsieweke <marian.buschsieweke@ovgu.de>
* @author Hugues Larrive <hugues.larrive@pm.me>
*/
#ifndef PERIPH_CONF_H
#define PERIPH_CONF_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name Clock configuration
* @{
*/
#ifndef CLOCK_CORECLOCK
/* Using 8MHz internal oscillator as default clock source */
#define CLOCK_CORECLOCK (8000000UL)
#endif
/** @} */
#ifdef __cplusplus
}
#endif
#include "periph_conf_atmega_common.h"
#endif /* PERIPH_CONF_H */
/** @} */

25
boards/common/atmega/include/periph_conf_atmega_common.h
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@ -6,6 +6,7 @@
* 2017 HAW Hamburg, Dimitri Nahm
* 2018 Matthew Blue <matthew.blue.neuro@gmail.com>
* 2019 Otto-von-Guericke-Universität Magdeburg
* 2023 Hugues Larrive
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
@ -28,6 +29,7 @@
* @author Matthew Blue <matthew.blue.neuro@gmail.com>
* @author Francisco Acosta <francisco.acosta@inria.fr>
* @author Marian Buschsieweke <marian.buschsieweke@ovgu.de>
* @author Hugues Larrive <hugues.larrive@pm.me>
*/
#ifndef PERIPH_CONF_ATMEGA_COMMON_H
@ -71,6 +73,12 @@ extern "C" {
#define UART_1 MEGA_UART1
#define UART_1_ISR USART1_RX_vect
#define UART_1_ISR_TX USART1_TX_vect
#elif defined(CPU_ATMEGA8)
#define UART_NUMOF (1U)
#define UART_0 MEGA_UART
#define UART_0_ISR USART_RXC_vect
#define UART_0_ISR_TX USART_TXC_vect
#elif defined(CPU_ATMEGA328P)
#define UART_NUMOF (1U)
@ -156,7 +164,8 @@ extern "C" {
*/
#ifndef ADC_NUMOF
#if defined(CPU_ATMEGA128RFA1) || defined(CPU_ATMEGA256RFR2) || defined(CPU_ATMEGA328P) || \
defined(CPU_ATMEGA1281) || defined(CPU_ATMEGA1284P) || defined(CPU_ATMEGA32U4)
defined(CPU_ATMEGA1281) || defined(CPU_ATMEGA1284P) || defined(CPU_ATMEGA32U4) || \
defined(CPU_ATMEGA8)
#define ADC_NUMOF (8U)
#elif defined (CPU_ATMEGA2560)
#define ADC_NUMOF (16U)
@ -180,7 +189,9 @@ extern "C" {
* @{
*/
#ifndef PWM_NUMOF
#if defined(CPU_ATMEGA328P)
#if defined(CPU_ATMEGA8)
#define PWM_PINS_CH0 { GPIO_PIN(PORT_B, 3), GPIO_UNDEF }
#elif defined(CPU_ATMEGA328P)
#define PWM_PINS_CH0 { GPIO_PIN(PORT_D, 6), GPIO_PIN(PORT_D, 5) }
#define PWM_PINS_CH1 { GPIO_PIN(PORT_B, 3), GPIO_PIN(PORT_D, 3) }
#elif defined(CPU_ATMEGA1281)
@ -200,8 +211,9 @@ extern "C" {
#if defined(CPU_ATMEGA32U4) || defined(CPU_ATMEGA328P) || \
defined(CPU_ATMEGA1281) || defined(CPU_ATMEGA1284P) || \
defined(CPU_ATMEGA2560)
defined(CPU_ATMEGA2560) || defined(CPU_ATMEGA8)
static const pwm_conf_t pwm_conf[] = {
#ifndef CPU_ATMEGA8
{
.dev = MINI_TIMER0,
.pin_ch = PWM_PINS_CH0,
@ -213,6 +225,13 @@ extern "C" {
.pin_ch = PWM_PINS_CH1,
.div = MINI_TIMER2_DIV,
}
#endif
#else /* CPU_ATMEGA8 */
{
.dev = MINI_TIMER2,
.pin_ch = PWM_PINS_CH0,
.div = MINI_TIMER2_DIV,
},
#endif
};