| /* |
| * Copyright 2010 The Android Open-Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License |
| */ |
| |
| /* |
| * Define the basic structure for messages from the host. |
| * Messages are MESSAGE_SIZE bytes, with a 2-byte opcode, a 2-byte |
| * unique ID defined by the sender, and the remainder payload. |
| * The remaining 2 bytes must be 0xFEEDFACE. This is used by |
| * the message handler as a tail sentinel to resync with the |
| * sender in case data is lost and the fixed-byte messages |
| * get out of sync. |
| */ |
| #define MESSAGE_SIZE 128 |
| #define MESSAGE_DELIMITER 0xBEEF |
| #define MESSAGE_ESCAPE 0x2a |
| struct message { |
| uint16_t opcode; |
| uint16_t id; |
| uint8_t data[MESSAGE_SIZE - 6]; |
| uint16_t tail; |
| }; |
| struct message CURRENT_MESSAGE; |
| |
| #define OPCODE_RESET 0x00 |
| struct reset { |
| uint16_t opcode; |
| uint16_t id; |
| uint8_t unused[MESSAGE_SIZE - 4]; |
| }; |
| |
| #define OPCODE_INIT_TIME (OPCODE_RESET + 1) |
| struct init_time { |
| uint16_t opcode; |
| uint16_t id; |
| uint32_t cur_raw_time; |
| uint8_t unused[MESSAGE_SIZE - 6]; |
| }; |
| |
| #define OPCODE_CURRENT_TIME (OPCODE_RESET + 2) |
| struct current_time { // we never actually use this, but here for consistency |
| uint16_t opcode; |
| uint16_t id; |
| uint8_t unused[MESSAGE_SIZE - 4]; |
| }; |
| |
| #define OPCODE_SETMODE_PONG (OPCODE_RESET + 3) |
| struct setmode_pong { |
| uint16_t opcode; |
| uint16_t id; |
| uint16_t playfield_width; |
| uint16_t playfield_height; |
| uint16_t paddle_width; |
| uint16_t paddle_offset; |
| uint16_t max_paddle_motion; |
| uint8_t unused[MESSAGE_SIZE - 14]; |
| }; |
| |
| #define OPCODE_PONG_BALL_STATE (OPCODE_RESET + 4) |
| struct pong_ball_state { |
| uint16_t opcode; |
| uint16_t id; |
| uint16_t ball_x; |
| uint16_t ball_y; |
| uint8_t unused[MESSAGE_SIZE - 8]; |
| }; |
| |
| struct wall_time_struct { |
| uint32_t raw; // long == 4-byte on AVR |
| uint8_t initialized; |
| uint8_t hours; |
| uint8_t minutes; |
| uint8_t seconds; |
| }; |
| struct wall_time_struct WALL_TIME; |
| |
| struct pong_state_struct { |
| uint16_t playfield_width; |
| uint16_t playfield_height; |
| uint16_t paddle_width; |
| uint16_t paddle_offset; |
| uint16_t max_paddle_motion; |
| uint16_t paddle_x; |
| uint16_t last_ball_x; |
| uint16_t last_ball_y; |
| }; |
| struct pong_state_struct PONG_STATE; |
| |
| |
| void print_current_time() { |
| if (WALL_TIME.initialized) { |
| Serial.print("current_time="); |
| Serial.print(WALL_TIME.hours, DEC); |
| Serial.print(":"); |
| if (WALL_TIME.minutes < 10) |
| Serial.print("0"); |
| Serial.print(WALL_TIME.minutes, DEC); |
| Serial.print(":"); |
| if (WALL_TIME.seconds < 10) |
| Serial.print("0"); |
| Serial.println(WALL_TIME.seconds, DEC); |
| } else { |
| Serial.println("current_time=00:00:00"); |
| } |
| } |
| |
| |
| void handle_current_message() { |
| static uint16_t last_id; |
| static struct setmode_pong* setmode_pong_msg; |
| static struct pong_ball_state* pong_ball_state_msg; |
| static uint16_t paddle_half_width; |
| static uint16_t paddle_max; |
| static uint16_t danger; |
| static uint8_t invert; |
| static uint16_t delta; |
| |
| if (CURRENT_MESSAGE.id == 0 || CURRENT_MESSAGE.id == last_id) { |
| return; |
| } |
| last_id = CURRENT_MESSAGE.id; |
| |
| switch (CURRENT_MESSAGE.opcode) { |
| |
| case OPCODE_SETMODE_PONG: |
| memset(&PONG_STATE, 0, sizeof(PONG_STATE)); |
| setmode_pong_msg = (struct setmode_pong*)(&CURRENT_MESSAGE); |
| PONG_STATE.playfield_width = setmode_pong_msg->playfield_width; |
| PONG_STATE.playfield_height = setmode_pong_msg->playfield_height; |
| PONG_STATE.paddle_width = setmode_pong_msg->paddle_width; |
| PONG_STATE.paddle_offset = setmode_pong_msg->paddle_offset; |
| PONG_STATE.max_paddle_motion = setmode_pong_msg->max_paddle_motion; |
| |
| paddle_half_width = PONG_STATE.paddle_width / 2; |
| paddle_max = PONG_STATE.playfield_width - paddle_half_width; |
| |
| Serial.println("message_type=setmode_pong_ack"); |
| Serial.print("id="); |
| Serial.println(CURRENT_MESSAGE.id); |
| print_current_time(); |
| Serial.println(""); |
| break; |
| |
| case OPCODE_PONG_BALL_STATE: |
| pong_ball_state_msg = (struct pong_ball_state*)(&CURRENT_MESSAGE); |
| danger = pong_ball_state_msg->ball_x - PONG_STATE.paddle_x; |
| invert = (danger < 0); |
| danger *= invert ? -1 : 1; |
| if (danger < paddle_half_width) { |
| delta = 0; |
| } else if (danger < PONG_STATE.playfield_width / 3) { |
| delta = PONG_STATE.max_paddle_motion / 3; |
| } else if (danger < PONG_STATE.playfield_width * 2 / 3) { |
| delta = PONG_STATE.max_paddle_motion * 2 / 3; |
| } else { |
| delta = PONG_STATE.max_paddle_motion; |
| } |
| delta *= invert ? 1 : -1; |
| PONG_STATE.paddle_x += delta; |
| if (PONG_STATE.paddle_x < paddle_half_width) { |
| PONG_STATE.paddle_x = paddle_half_width; |
| } else if (PONG_STATE.paddle_x > paddle_max) { |
| PONG_STATE.paddle_x = paddle_max; |
| } |
| |
| Serial.println("message_type=pong_paddle_state"); |
| Serial.print("id="); |
| Serial.println(CURRENT_MESSAGE.id); |
| print_current_time(); |
| Serial.print("paddle_x="); |
| Serial.println(PONG_STATE.paddle_x); |
| Serial.println(""); |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| /* This is a temporary buffer used by the message handler */ |
| struct message_buffer { |
| uint16_t count; // number of bytes read into the buffer |
| uint8_t buffer[MESSAGE_SIZE]; // contents of a 'struct message' |
| }; |
| struct message_buffer MESSAGE_BUFFER; |
| |
| /* |
| * Clears all stateful values, including the wall clock time, current message |
| * data, and user/app state. Also clears the message handler's buffer. By |
| * "clear" we mean "memset to 0". |
| */ |
| void reset() { |
| memset(&WALL_TIME, 0, sizeof(WALL_TIME)); |
| memset(&CURRENT_MESSAGE, 0, sizeof(CURRENT_MESSAGE)); |
| memset(&MESSAGE_BUFFER, 0, sizeof(MESSAGE_BUFFER)); |
| memset(&PONG_STATE, 0, sizeof(PONG_STATE)); |
| } |
| |
| |
| /* |
| * Pumps the message processor. That is, this function is intended to be |
| * called once per loop to read all pending Serial/TTL data, and decode a |
| * message from the peer if one is complete. In cases where data is corrupted |
| * (such as by dropping bytes), this function also attempts to re-sync with |
| * the host by discarding messages until it finds a MESSAGE_DELIMITER, after |
| * which is resyncs its buffer on the first subsequent byte. |
| * |
| * This functional also handles two low-level 'system' messages: a reset |
| * instruction which invokes reset(), and an init_time instruction which |
| * provides the soft clock with the current time so that it can start keeping |
| * time. |
| */ |
| void pump_message_processor() { |
| static uint8_t cur_byte; |
| static uint16_t* cur_word; |
| static int8_t delimiter_index; |
| static char buf[4]; |
| while (Serial.available() > 0) { // keep going as long as we might have messages |
| cur_byte = (uint8_t)(Serial.read() & 0x000000ff); |
| MESSAGE_BUFFER.buffer[(MESSAGE_BUFFER.count)++] = cur_byte; |
| Serial.print("booga "); |
| Serial.print(itoa(MESSAGE_BUFFER.count, buf, 10)); |
| Serial.print(" "); |
| Serial.print(itoa(Serial.available(), buf, 10)); |
| Serial.print(" "); |
| Serial.println(itoa(cur_byte, buf, 10)); |
| if (MESSAGE_BUFFER.count >= MESSAGE_SIZE) { |
| if ((*(uint16_t*)(MESSAGE_BUFFER.buffer + MESSAGE_SIZE - 2)) != MESSAGE_DELIMITER) { |
| // whoops, we got out of sync with the transmitter. Scan current |
| // buffer for the delimiter, discard previous message, and shift |
| // partial next message to front of buffer. This loses a message but |
| // gets us back in sync |
| delimiter_index = -2; |
| for (int i = MESSAGE_SIZE - 2; i >= 0; --i) { |
| if (*((uint16_t*)(MESSAGE_BUFFER.buffer + i)) == MESSAGE_DELIMITER) { |
| if (((i - 1) >= 0) && (MESSAGE_BUFFER.buffer[i - 1] != MESSAGE_ESCAPE)) { |
| delimiter_index = i; |
| break; |
| } |
| } |
| } |
| Serial.print("klaxon "); |
| Serial.println(itoa(delimiter_index, buf, 10)); |
| Serial.print("klaxon "); |
| Serial.println(itoa(*((uint16_t*)(MESSAGE_BUFFER.buffer + MESSAGE_SIZE - 2)), buf, 10)); |
| MESSAGE_BUFFER.count = 0; |
| if (delimiter_index >= 0) { |
| for (int i = delimiter_index + 2; i < MESSAGE_SIZE; ++i, ++(MESSAGE_BUFFER.count)) { |
| MESSAGE_BUFFER.buffer[MESSAGE_BUFFER.count] = MESSAGE_BUFFER.buffer[i]; |
| } |
| } |
| memset(MESSAGE_BUFFER.buffer + MESSAGE_BUFFER.count, 0, MESSAGE_SIZE - MESSAGE_BUFFER.count); |
| } else { |
| memcpy(&CURRENT_MESSAGE, MESSAGE_BUFFER.buffer, MESSAGE_SIZE); |
| memset(&MESSAGE_BUFFER, 0, sizeof(MESSAGE_BUFFER)); |
| switch (CURRENT_MESSAGE.opcode) { |
| case OPCODE_RESET: |
| reset(); |
| return; |
| |
| case OPCODE_INIT_TIME: |
| // cast CURRENT_MESSAGE to our time struct to conveniently fetch |
| // out the current time |
| WALL_TIME.raw = ((struct init_time*)(&CURRENT_MESSAGE))->cur_raw_time; |
| WALL_TIME.initialized = 1; |
| |
| Serial.println("message_type=init_time_ack"); |
| Serial.print("id="); |
| Serial.println(CURRENT_MESSAGE.id); |
| print_current_time(); |
| Serial.println(""); |
| |
| CURRENT_MESSAGE.id = 0; |
| break; |
| |
| case OPCODE_CURRENT_TIME: |
| Serial.println("message_type=current_time_ack"); |
| Serial.print("id="); |
| Serial.println(CURRENT_MESSAGE.id); |
| print_current_time(); |
| Serial.println(""); |
| |
| CURRENT_MESSAGE.id = 0; |
| |
| default: |
| // no-op -- actually means main loop will handle it |
| break; |
| } |
| } |
| } |
| } |
| } |
| |
| /* |
| * Pumps the system wall clock. This checks the device's monotonic clock to |
| * determine elapsed time since last invocation, and updates wall clock time |
| * by dead reckoning. Since the device has no battery backup, a power-off will |
| * lose the current time, so timekeeping cannot begin until an INIT_TIME |
| * message is received. (The pump_message_processor() function handles that.) |
| * |
| * Once timekeeping is underway, current time is exposed to user/app code via |
| * the WALL_TIME object, which has 24-hour HH/MM/SS fields. |
| */ |
| void pump_clock() { |
| static uint32_t prev_millis = 0; |
| static uint32_t tmp_prev_millis = 0; |
| uint32_t tmp = 0; |
| |
| if (millis() / 1000 != tmp_prev_millis) { |
| tmp_prev_millis = millis() / 1000; |
| print_current_time(); |
| } |
| |
| if (WALL_TIME.initialized) { |
| tmp = millis() / 1000; |
| if (tmp != prev_millis) { |
| prev_millis = tmp; |
| WALL_TIME.raw++; |
| } |
| WALL_TIME.seconds = WALL_TIME.raw % 60; |
| WALL_TIME.minutes = (WALL_TIME.raw / 60) % 60; |
| WALL_TIME.hours = (WALL_TIME.raw / (60 * 60)) % 24; |
| } |
| } |
| |
| |
| /* |
| * Standard Arduino setup hook. |
| */ |
| void setup() { |
| Serial.begin(115200); |
| } |
| |
| |
| /* |
| * Standard Arduino loop-pump hook. |
| */ |
| void loop() { |
| static uint16_t last_id = 0; |
| |
| // pump the clock and message processor |
| pump_clock(); |
| pump_message_processor(); |
| |
| // ignore any "system" messages (those with ID == 0) but dispatch app messages |
| if ((last_id != CURRENT_MESSAGE.id) && (CURRENT_MESSAGE.id != 0)) { |
| handle_current_message(); |
| } |
| last_id = CURRENT_MESSAGE.id; |
| } |