Detailed Description

This is just a ATTINY84A-PU on a breadboard with a USB/Serial adapter and a LED connected at pin #7 (PA6/OC1A). No crystal.

The serial communication uses 1 wire for RX/TX. The AVR communication pin is connected to the RXD pin of the serial adapter and a 1k resistor is connected between the RXD and TXD pins (it could be replaced by a diode, Schottky preferably).

Pin Configuration

                      Vcc o   U   o Gnd
           XTAL1 CLKI PB0 o       o PA0 ADC0 AREF
                XTAL2 PB1 o       o PA1 ADC1 AIN0
                RESET PB3 o       o PA2 ADC2 AIN1
      INT0 OC0A CKOUT PB2 o       o PA3 ADC3 T0
        ICP OC0B ADC7 PA7 o       o PA4 ADC4 USCK SCL T1
OC1A SDA MOSI DI ADC6 PA6 o       o PA5 ADC5 DO MISO OC1B

Serial adapter wiring

TINY84 ->  2 : RXD <- Serial Adapter
             : TXD
           4 : DTR
          14 : GND
           1 : VCC

USBASP wiring

 USBASP -> 1  MOSI  7  <- TINY84
           2  VCC   1
           4  GND   14
           5  RST   4
           7  SCK   9
           9  MISO  8

attiny84.h: /* This file is part of the HWA project.

* Copyright (c) 2012,2015 Christophe Duparquet.

* All rights reserved. Read LICENSE.TXT for details.

*/

#define HW_DEVICE_CLK_SRC rc_8MHz

#define HW_DEVICE_CLK_PSC 1

#define HW_DEVICE_EXTERNAL_RESET enabled

#define HW_DEVICE_SELF_PROGRAMMING enabled

#define HW_DEVICE_DEBUG_WIRE disabled

#define HW_DEVICE_WATCHDOG_ALWAYS_ON no

#define HW_DEVICE_CLOCK_OUTPUT disabled

#define HW_DEVICE_BROWNOUT_DETECTION 2500_2900mV

#define DIABOLO_PIN_RX (pin,2)

#define DIABOLO_PIN_TX (pin,2)

#define DIABOLO_SYNC 51

#define PIN_LED (pin,7) /* OC1A */

//#define PIN_LED (pin,5) /* OC0A */

#define PIN_ANALOG_INPUT (pin,13) /* ADC0 */

/* Pins for hw_swuart1

*/

#define PIN_TX2 (pin,8)

#define PIN_RX2 (pin,9)

/* Include HWA definitions

*/

#include <hwa/attiny84a_pu.h>

Device configuration
#define	HW_DEVICE_CLK_SRC rc_8MHz

#define	HW_DEVICE_CLK_PSC 1

#define	HW_DEVICE_EXTERNAL_RESET enabled

#define	HW_DEVICE_SELF_PROGRAMMING enabled

#define	HW_DEVICE_DEBUG_WIRE disabled

#define	HW_DEVICE_WATCHDOG_ALWAYS_ON no

#define	HW_DEVICE_CLOCK_OUTPUT disabled

#define	HW_DEVICE_BROWNOUT_DETECTION 2500_2900mV

Settings for the Diabolo bootloader
Settings for the Diabolo application are in the board's Makefile
#define	DIABOLO_PIN_RX (pin,2)

#define	DIABOLO_PIN_TX (pin,2)

#define	DIABOLO_SYNC 51

Board pins
The pin at which the LED is connected. The target device name indicates its package, then pin numbers can be used as well as pin names.
#define	PIN_LED (pin,7) /* OC1A */

#define	PIN_ANALOG_INPUT (pin,13) /* ADC0 */

#define	PIN_TX2 (pin,8)

#define	PIN_RX2 (pin,9)

Macro Definition Documentation

◆ DIABOLO_PIN_RX

#define DIABOLO_PIN_RX (pin,2)

Examples: hwa/atmel/avr/examples/05-2-swuart-sync-rx-tx/main.c.

◆ DIABOLO_PIN_TX

#define DIABOLO_PIN_TX (pin,2)

◆ DIABOLO_SYNC

#define DIABOLO_SYNC 51

◆ HW_DEVICE_BROWNOUT_DETECTION

#define HW_DEVICE_BROWNOUT_DETECTION 2500_2900mV

◆ HW_DEVICE_CLK_PSC

#define HW_DEVICE_CLK_PSC 1

◆ HW_DEVICE_CLK_SRC

#define HW_DEVICE_CLK_SRC rc_8MHz

◆ HW_DEVICE_CLOCK_OUTPUT

#define HW_DEVICE_CLOCK_OUTPUT disabled

◆ HW_DEVICE_DEBUG_WIRE

#define HW_DEVICE_DEBUG_WIRE disabled

◆ HW_DEVICE_EXTERNAL_RESET

#define HW_DEVICE_EXTERNAL_RESET enabled

◆ HW_DEVICE_SELF_PROGRAMMING

#define HW_DEVICE_SELF_PROGRAMMING enabled

◆ HW_DEVICE_WATCHDOG_ALWAYS_ON

#define HW_DEVICE_WATCHDOG_ALWAYS_ON no

◆ PIN_ANALOG_INPUT

#define PIN_ANALOG_INPUT (pin,13) /* ADC0 */

Examples: hwa/atmel/avr/examples/10-1-acmp/main.c.

◆ PIN_LED

#define PIN_LED (pin,7) /* OC1A */

◆ PIN_RX2

#define PIN_RX2 (pin,9)

◆ PIN_TX2

#define PIN_TX2 (pin,8)