The following code comes from AtTiny serial library that I want to use:
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
// change these to use another pin
#define TX_PORT PORTB
#define TX_PIN PB0
#define TX_DDR DDRB
#define TX_DDR_PIN DDB0
I have no idea which pins to connect. What do these constants mean and where are they documented?
The mapping can be found in the io.h file but also in Arduino core files.
Below is the pin mapping:
ATtinyX4
+----U----+
(VCC)-------------1-|VCC GND|-14------------(GND)
(D10)-------------2-|PB0 PA0|-13----------(D0/A0)
(D9)--------------3-|PB1 PA1|-12----------(D1/A1)
(/RESET)----------4-|PB3 PA2|-11----------(D2/A2)
(D8)--------------5-|PB2 PA3|-10-------(D3/A3/SS)
(D7/A7)-----------6-|PA7 PA4|-9---(D4/A4/SCL/SCK)
(MISO/SDA/D6/A6)--7-|PA6 PA5|-8------(D5/A5/MOSI)
+---------+
The serial library uses:
#define TX_PIN PB0
Which is ATtinyX4 Pin #2, or Arduino attiny core digital pin D10 https://github.com/damellis/attiny/blob/master/variants/tiny14/pins_arduino.h.
Cheers
