Board attiny85-3v3

This is a single ATTINY85-20PU without crystal on a breadboard with a USB/Serial adapter for 1-wire communication, a LED connected at pin #5 (PB0/OC0A), one analog input pin.

Pin Configuration

           RESET ADC0 PB5 o   U   o Vcc
XTAL1 CLKI /OC1B ADC3 PB3 o       o PB2 SCK USCK SCL ADC1 T0 INT0
 XTAL2 CLKO OC1B ADC2 PB4 o       o PB1 MISO DO AIN1 OC0B OC1A
                      Gnd o       o PB0 MOSI DI SDA AIN0 OC0A /OC1A AREF

Serial adapter wiring

The serial communication uses 1 wire for RX/TX, AVR pin #2 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).

TINY85 ->  2 : RXD <- Serial Adapter
             : TXD
           1 : DTR
           4 : GND
           8 : VCC

To install Diabolo with avrdude/usbasp:

 USBASP -> 1  MOSI  5 <- TINY85
           2  VCC   8
           4  GND   4
           5  RST   1
           7  SCK   7
           9  MISO  6

attiny85-3v3.h

 
/*  This file is part of the HWA project.
 *  Copyright (c) 2016 Christophe Duparquet.
 *  All rights reserved. Read LICENSE.TXT for details.
 */
 
/*  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
#define HW_DEVICE_STARTUP_DELAYS        6CK_14CK_64ms
 
/*  Settings for building 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
 
/*  The pin at which the LED is connected. The target device name indicates its
 *  package, then pins named by their number can be used.
 */
#define PIN_LED                         (pin,5) // OC0A
 
/*  Analog input pin
 */
#define PIN_ANALOG_INPUT                (pin,7) // ADC1
 
/*  HWA
 */
#include <hwa/attiny85_20pu.h>