diff --git a/ball_and_beam-2018/avr/Makefile b/ball_and_beam-2018/avr/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..a33ef6ba133b96cad790822960e538fb9762a3c3
--- /dev/null
+++ b/ball_and_beam-2018/avr/Makefile
@@ -0,0 +1,10 @@
+TARGETS=ball_and_beam-2018
+
+ball_and_beam-2018.ARCH=avr
+ball_and_beam-2018.CHIP=atmega32
+# 14.7456 MHz crystal, brown out
+ball_and_beam-2018.FUSE_L=0x1f
+ball_and_beam-2018.FUSE_H=0xd9
+ball_and_beam-2018.C=ball_and_beam-2018
+
+include ../../lib/avr/Makefile.common
diff --git a/ball_and_beam-2018/avr/ball_and_beam-2018.c b/ball_and_beam-2018/avr/ball_and_beam-2018.c
new file mode 100644
index 0000000000000000000000000000000000000000..4e7ac39d1918d4950cbd76d6679ad93d1e456dc7
--- /dev/null
+++ b/ball_and_beam-2018/avr/ball_and_beam-2018.c
@@ -0,0 +1,250 @@
+#include <avr/eeprom.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <inttypes.h>
+#include "serialio.h"
+
+/*
+ * Serial I/O assignments:
+ *
+ * DI 0 -- Motor Overtemp
+ *
+ * DO 0 -- Motor Brake
+ * DO 1 -- Accelerometer Self-Test
+ *
+ * AI 0 -- Ball Position
+ * AI 1 -- Motor Current
+ * AI 2 -- Accelerometer X
+ * AI 3 -- Accelerometer Y
+ * AI 4 -- Accelerometer Z
+ * EI 5 -- Motor Position
+ *
+ * AO 0 -- Motor Speed
+ */
+
+/*
+ * Used I/O pins
+ *
+ * PA0 Ball Position
+ * PA1 Motor Current
+ * PA2 Accelerometer X
+ * PA3 Accelerometer Y
+ * PA4 Accelerometer Z
+ *
+ * PB0 Ball On Beam
+ * PB1 Motor direction
+ * PB2 Encoder Z
+ * PB3 Motor Brake
+ * PB4 Motor Thermal Flag
+ * PB5 Programming MOSI
+ * PB6 Programming MISO
+ * PB7 Programming SCK
+ *
+ * PD0 Serial In
+ * PD1 Serial Out
+ * PD2 Encoder A
+ * PD3 Encoder B
+ * PD5 Motor PWM
+ */
+
+volatile unsigned char error;
+
+
+volatile uint8_t serial_readbits;
+volatile uint8_t serial_readchannels;
+volatile uint8_t serial_readconfig;
+
+struct values {
+ /* Outputs */
+ uint8_t motorBrake;
+ uint16_t motorSpeed;
+ uint8_t accelerometerSelfTest;
+
+ /* Inputs */
+ int16_t ballPosition;
+ int16_t motorCurrent;
+ int16_t accelerometerX;
+ int16_t accelerometerY;
+ int16_t accelerometerZ;
+ int32_t motorEncoder;
+ int8_t motorThermalFlag;
+ int8_t ballOnBeam;
+ uint8_t timer;
+};
+volatile struct values global;
+
+SIGNAL(ADC_vect)
+{
+ unsigned char channel = ADMUX & 0x0f;
+ unsigned int value = ADCW;
+
+ if (global.timer) {
+ global.timer--;
+ PORTD &= ~0x40;
+ } else {
+ PORTD |= 0x40;
+ }
+ switch (channel) {
+ case 0: {
+ channel = 1;
+ global.ballPosition = value;
+ } break;
+ case 1: {
+ channel = 2;
+ global.motorCurrent = value;
+ } break;
+ case 2: {
+ channel = 3;
+ global.accelerometerX = value;
+ } break;
+ case 3: {
+ channel = 4;
+ global.accelerometerY = value;
+ } break;
+ case 4: {
+ channel = 5;
+ global.accelerometerZ = value;
+ } break;
+ default: {
+ channel = 0;
+ } break;
+ }
+ ADMUX = 0x00 | channel; // Vref = external, right adjust
+ ADCSRA = 0xcf; // Enable ADC interrupts, Clock/128
+}
+
+typedef enum { cmd_clear_bit, cmd_set_bit,
+ cmd_read_bit, cmd_read_chan } command;
+
+SIGNAL(USART_RXC_vect)
+{
+ char ch = UDR;
+
+ global.timer = 0xff;
+ switch (serialio_RXC(ch)) {
+ case serialio_clearbit: {
+ switch (serialio_channel) {
+ case 0: { PORTB &= ~0x08; } break;
+ case 1: { PORTC &= ~0x80; } break;
+ }
+ } break;
+ case serialio_setbit: {
+ switch (serialio_channel) {
+ case 0: { PORTB |= 0x08; } break;
+ case 1: { PORTC |= 0x80; } break;
+ }
+ } break;
+ case serialio_pollbit: {
+ if (serialio_channel < 1) {
+ serial_readbits |= (1<<serialio_channel);
+ }
+ } break;
+ case serialio_pollchannel: {
+ if (serialio_channel < 6) {
+ serial_readchannels |= (1<<serialio_channel);
+ } else if (serialio_channel == 31) {
+ serial_readconfig = 1;
+ }
+ } break;
+ case serialio_setchannel: {
+ switch (serialio_channel) {
+ case 0: {
+ int16_t speed;
+ if (serialio_value < 0x400) {
+ speed = 0x400 - serialio_value;
+ PORTB |= 0x02;
+ } else {
+ speed = serialio_value - 0x400;
+ PORTB &= ~0x02;
+ }
+ OCR1A = speed & 0x3ff;
+ } break;
+ } break;
+ } break;
+ case serialio_error: {
+ } break;
+ case serialio_more: {
+ } break;
+ }
+}
+
+int main()
+{
+ serialio_init();
+ serial_readbits = 0;
+ serial_readchannels = 0;
+ serial_readconfig = 0;
+ PORTA = 0x00; // PortA, pull-ups
+ DDRA = 0x00; // PortA, all inputs
+ PORTB = 0x00; // PortB, pull-ups / initial values
+ DDRB = 0x0a; // PortB, bits 1 & 3 outputs
+ PORTC = 0x00; // PortC, pull-ups / initial values
+ DDRC = 0x80; // PortC, bit 7 output
+ PORTD = 0x00; // PortD, pull-ups / initial values
+ DDRD = 0x20; // PortD, bit 5 output
+ TCCR0 = 0x05; // Timer0, Clock / 1024
+ TCCR1A = 0x83; // OC1A 10 bit PWM (Phase Correct), clear A on match
+ TCCR1B = 0x01; // Clock / 1
+ OCR1A = 0 & 0x3ff;
+ UCSRA = 0x00; // USART:
+ UCSRB = 0x98; // USART: RxIntEnable|RxEnable|TxEnable
+ UCSRC = 0x86; // USART: 8bit, no parity
+ UBRRH = 0; // USART: 115200 @ 14.7456MHz
+ UBRRL = 7; // USART: 115200 @ 14.7456MHz
+ ADMUX = 0x00; // Vref = external, right adjust
+ ADMUX = 0x0e; // Vref = external, right adjust, read 1.22V (Vbg)
+ ADCSRA = 0xcf; // Enable ADC interrupts, Clock/128
+
+ SREG = 0x80; // Global interrupt enable
+ while (1) {
+ unsigned char bits, channels, config;
+ struct values local;
+
+ SREG = 0x00; // Global interrupt disable
+ bits = serial_readbits;
+ serial_readbits = 0;
+ channels = serial_readchannels;
+ serial_readchannels = 0;
+ config = serial_readconfig;
+ serial_readconfig = 0;
+ local = global;
+ SREG = 0x80; // Global interrupt enable
+ if (channels & 0x01) { serialio_putchannel(0, local.ballPosition); }
+ if (channels & 0x02) { serialio_putchannel(1, local.motorCurrent); }
+ if (channels & 0x04) { serialio_putchannel(2, local.accelerometerX); }
+ if (channels & 0x08) { serialio_putchannel(3, local.accelerometerY); }
+ if (channels & 0x10) { serialio_putchannel(4, local.accelerometerZ); }
+ if (channels & 0x20) { serialio_putchannel(5, local.motorEncoder); }
+ if (bits & 0x01) { serialio_putbit(0, PORTB & 0x10); } // thermalFlag
+ if (config) {
+ CONF_DIGITAL_IN(0, CONF_RESOLUTION(1)); // motorTemp
+
+ CONF_DIGITAL_OUT(0, CONF_RESOLUTION(1)); // motorBrake
+ CONF_DIGITAL_OUT(1, CONF_RESOLUTION(1)); // accelerometerSelfTest
+
+ CONF_ANALOG_IN(0, CONF_RESOLUTION(10)); // ballPosition
+ CONF_ANALOG_IN(0, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(0, CONF_MAX(CONF_POSITIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(1, CONF_RESOLUTION(10)); // motorCurrent
+ CONF_ANALOG_IN(1, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(1, CONF_MAX(CONF_POSITIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(2, CONF_RESOLUTION(10)); // accelerometerX
+ CONF_ANALOG_IN(2, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(2, CONF_MAX(CONF_POSITIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(3, CONF_RESOLUTION(10)); // accelerometerY
+ CONF_ANALOG_IN(3, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(3, CONF_MAX(CONF_POSITIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(4, CONF_RESOLUTION(10)); // accelerometerZ
+ CONF_ANALOG_IN(4, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(10000)));
+ CONF_ANALOG_IN(4, CONF_MAX(CONF_POSITIVE_MILLIVOLT(10000)));
+ CONF_ENCODER_IN(5, CONF_RESOLUTION(32)); // motorPosition
+
+ CONF_ANALOG_OUT(0, CONF_RESOLUTION(11)); // motorSpeed
+ CONF_ANALOG_OUT(0, CONF_MIN(CONF_NEGATIVE_MILLIVOLT(12000)));
+ CONF_ANALOG_OUT(0, CONF_MAX(CONF_POSITIVE_MILLIVOLT(12000)));
+
+ CONF_END();
+ }
+ }
+}
+