AVR Assembly Tutorials

 avr_usart.h

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1 

35 #ifndef AVR_USART_H_

36 #define AVR_USART_H_

37 

38 #include <avr/io.h>

39 #include <avr/interrupt.h>

40 #include "avr_macros.h"

41 #include "avr_utils.h"

42 

43 #pragma message ( "avr_usart.h included" )

44 

49 #define USART_SYNCHRONOUS_CLOCK_PRIORITY 0

50 #define USART_MODE_ASYNCHRONOUS (0<<UMSEL00)

51 #define USART_MODE_SYNCHRONOUS (1<<UMSEL00) | USART_SYNCHRONOUS_CLOCK_PRIORITY

52 #define USART_MODE_MASK (1<<UMSEL00)

59 #define USART_PARITY_BIT_NO (0<<UPM00)

60 #define USART_PARITY_BIT_EVEN (1<<UPM01)

61 #define USART_PARITY_BIT_ODD (1<<UPM01) | (1<<UPM00)

62 #define USART_PARITY_BIT_MASK (1<<UPM01) | (1<<UPM00)

69 #define USART_STOP_BIT_ONE (0<<USBS0)

70 #define USART_STOP_BIT_TWO (1<<USBS0)

71 #define USART_STOP_BIT_MASK (1<<USBS0)

78 #define USART_DATA_BIT_FIVE (0<<UCSZ00)

79 #define USART_DATA_BIT_SIX (1<<UCSZ00)

80 #define USART_DATA_BIT_SEVEN (1<<UCSZ01)

81 #define USART_DATA_BIT_EIGHT (1<<UCSZ01) | (1<<UCSZ00)

82 #define USART_DATA_BIT_MASK (1<<UCSZ01) | (1<<UCSZ00)

89 #define USART_RX_COMPLETE_INTERRUPT (1<<RXCIE0)

90 #define USART_TX_COMPLETE_INTERRUPT (1<<TXCIE0)

91 #define USART_DATA_REGISTER_EMPTY_INTERRUPT (1<<UDRIE0)

98 typedef struct USART_ConfigData

99 {

100  uint8_t UsartMode;

101  uint16_t BaudRate;

102  uint8_t ParityBit;

103  uint8_t StopBit;

104  uint8_t DataBit;

105 } USART_ConfigData;

112 static volatile uint8_t *USART_TransmitBuffer;

113 static volatile uint8_t USART_TransmitBusyFlag = 0;

114 static volatile uint16_t USART_TransmitBufferIndex = 0;

115 static volatile uint16_t USART_TransmitBufferLength = 0;

117 static volatile uint8_t *USART_ReceiveBuffer;

118 static volatile uint8_t USART_ReceiveBusyFlag = 0;

119 static volatile uint16_t USART_ReceiveBufferIndex = 0;

120 static volatile uint16_t USART_ReceiveBufferLength = 0;

127 void USART_FlushTransmitBuffer();

128 void USART_FlushReceiveBuffer();

135 inline void USART_EnableTransmitInterrupt();

136 inline void USART_DisableTransmitInterrupt();

143 inline void USART_EnableReceiveInterrupt();

144 inline void USART_DisableReceiveInterrupt();

151 void USART_Init(USART_ConfigData Data);

152 void USART_DeInit();

159 uint8_t USART_ReceiveBlocking();

160 uint8_t USART_ReceiveByte(uint8_t *Buffer);

161 uint8_t USART_ReceiveTwoBytes(uint16_t *Buffer);

162 uint8_t USART_ReceiveBytes(uint8_t *Buffer, uint16_t Size);

163 uint8_t USART_ReceiveChar(char *Character);

164 uint8_t USART_ReceiveInt(int *Number, uint8_t Size);

165 uint8_t USART_ReceiveLong(long *Number, uint8_t Size);

166 uint8_t USART_ReceiveString(char *Buffer, uint16_t Size);

167 void USART_CancelReceive();

174 uint8_t USART_TransmitBlocking(uint8_t *Buffer);

175 uint8_t USART_TransmitByte(uint8_t *Buffer);

176 uint8_t USART_TransmitTwoBytes(uint16_t *Buffer);

177 uint8_t USART_TransmitBytes(uint8_t *Buffer, uint16_t Size);

178 uint8_t USART_TransmitChar(char Character);

179 uint8_t USART_TransmitInt(int Number);

180 uint8_t USART_TransmitLong(long Number);

181 uint8_t USART_TransmitFloat(float Number, uint8_t Precision);

182 uint8_t USART_TransmitString(char *Buffer);

183 void USART_CancelTransmit();

191 void USART_FlushReceiveBuffer()

192 {

193  for (int i = 0; i < USART_ReceiveBufferLength; i++)

194  {

195  USART_ReceiveBuffer[i] = 0;

196  }

197 

198  USART_ReceiveBuffer = 0;

199  USART_ReceiveBusyFlag = 0;

200  USART_ReceiveBufferIndex = 0;

201  USART_ReceiveBufferLength = 0;

202 }

203 

209 void USART_FlushTransmitBuffer()

210 {

211  for (int i = 0; i < USART_TransmitBufferLength; i++)

212  {

213  USART_TransmitBuffer[i] = 0;

214  }

215 

216  USART_TransmitBuffer = 0;

217  USART_TransmitBusyFlag = 0;

218  USART_TransmitBufferIndex = 0;

219  USART_TransmitBufferLength = 0;

220 }

221 

227 inline void USART_EnableTransmitInterrupt()

228 {

229  UCSR0B |= USART_DATA_REGISTER_EMPTY_INTERRUPT;

230 }

231 

237 inline void USART_DisableTransmitInterrupt()

238 {

239  UCSR0B &= ~USART_DATA_REGISTER_EMPTY_INTERRUPT;

240 }

241 

247 inline void USART_EnableReceiveInterrupt()

248 {

249  UCSR0B |= USART_RX_COMPLETE_INTERRUPT;

250 }

251 

257 inline void USART_DisableReceiveInterrupt()

258 {

259  UCSR0B &= ~USART_RX_COMPLETE_INTERRUPT;

260 }

261 

276 void USART_Init(USART_ConfigData Data)

277 {

278  uint16_t USART_BaudPrescaler = 0;

279 

280  if (Data.UsartMode == (USART_MODE_ASYNCHRONOUS))

281  {

282  USART_BaudPrescaler = (((F_CPU / (Data.BaudRate * 16UL))) - 1);

283  }

284  else if (Data.UsartMode == (USART_MODE_SYNCHRONOUS))

285  {

286  USART_BaudPrescaler = (((F_CPU / (Data.BaudRate * 2UL))) - 1);

287  }

288 

289  /* Set Baud Rate */

290  UBRR0H = USART_BaudPrescaler >> 8;

291  UBRR0L = USART_BaudPrescaler;

292 

293  /* Set Frame Format */

294  UCSR0C = Data.UsartMode | Data.ParityBit | Data.StopBit | Data.DataBit;

295 

296  /* Enable Receiver and Transmitter */

297  UCSR0B = (1<<RXEN0) | (1<<TXEN0);

298 

299  /* Enable Global Interrupt */

300  sei();

301 }

302 

308 void USART_DeInit()

309 {

310  UCSR0B = 0x00;

311  UCSR0C = 0x06;

312 }

313 

319 uint8_t USART_ReceiveBlocking()

320 {

321  uint8_t DataByte;

322  while ((UCSR0A & (1<<RXC0)) == 0); // Do nothing until data have been received

323  DataByte = UDR0;

324  return DataByte;

325 }

326 

333 uint8_t USART_ReceiveByte(uint8_t *Buffer)

334 {

335  while (USART_ReceiveBusyFlag)

336  {

337  return BUSY;

338  }

339  USART_ReceiveBuffer = Buffer;

340  USART_ReceiveBufferLength = 1;

341  USART_ReceiveBufferIndex = 0;

342  USART_ReceiveBusyFlag = 1;

343  USART_EnableReceiveInterrupt();

344  return OK;

345 }

346 

353 uint8_t USART_ReceiveTwoBytes(uint16_t *Buffer)

354 {

355  while (USART_ReceiveBusyFlag)

356  {

357  return BUSY;

358  }

359  USART_ReceiveBuffer = (uint8_t*)Buffer;

360  USART_ReceiveBufferLength = 2;

361  USART_ReceiveBufferIndex = 0;

362  USART_ReceiveBusyFlag = 1;

363  USART_EnableReceiveInterrupt();

364  return OK;

365 }

366 

374 uint8_t USART_ReceiveBytes(uint8_t *Buffer, uint16_t Size)

375 {

376  if (Size == 0) return ERROR;

377 

378  while (USART_ReceiveBusyFlag)

379  {

380  return BUSY;

381  }

382  USART_ReceiveBuffer = Buffer;

383  USART_ReceiveBufferLength = Size;

384  USART_ReceiveBufferIndex = 0;

385  USART_ReceiveBusyFlag = 1;

386  USART_EnableReceiveInterrupt();

387  return OK;

388 }

389 

396 uint8_t USART_ReceiveChar(char *Character)

397 {

398  while (USART_ReceiveBusyFlag)

399  {

400  return BUSY;

401  }

402  USART_ReceiveBuffer = (uint8_t*)Character;

403  USART_ReceiveBufferLength = 1;

404  USART_ReceiveBufferIndex = 0;

405  USART_ReceiveBusyFlag = 1;

406  USART_EnableReceiveInterrupt();

407  return OK;

408 }

409 

417 uint8_t USART_ReceiveInt(int *Number, uint8_t Size)

418 {

419  if (Size == 0) return ERROR;

420 

421  char localbuffer[7] = {0};

422  while (USART_ReceiveBusyFlag)

423  {

424  return BUSY;

425  }

426  USART_ReceiveBuffer = (uint8_t*)localbuffer;

427  USART_ReceiveBufferLength = Size;

428  USART_ReceiveBufferIndex = 0;

429  USART_ReceiveBusyFlag = 1;

430  USART_EnableReceiveInterrupt();

431  while (USART_ReceiveBusyFlag);

432  *Number = UTILS_StringToInt(localbuffer);

433  return OK;

434 }

435 

443 uint8_t USART_ReceiveLong(long *Number, uint8_t Size)

444 {

445  if (Size == 0) return ERROR;

446 

447  char localbuffer[12] = {0};

448  while (USART_ReceiveBusyFlag)

449  {

450  return BUSY;

451  }

452  USART_ReceiveBuffer = (uint8_t*)localbuffer;

453  USART_ReceiveBufferLength = Size;

454  USART_ReceiveBufferIndex = 0;

455  USART_ReceiveBusyFlag = 1;

456  USART_EnableReceiveInterrupt();

457  while (USART_ReceiveBusyFlag);

458  *Number = UTILS_StringToLong(localbuffer);

459  return OK;

460 }

461 

469 uint8_t USART_ReceiveString(char *Buffer, uint16_t Size)

470 {

471  if (Size == 0) return ERROR;

472 

473  while (USART_ReceiveBusyFlag)

474  {

475  return BUSY;

476  }

477  USART_ReceiveBuffer = (uint8_t*)Buffer;

478  USART_ReceiveBufferLength = Size;

479  USART_ReceiveBufferIndex = 0;

480  USART_ReceiveBusyFlag = 1;

481  USART_EnableReceiveInterrupt();

482  return OK;

483 }

484 

490 void USART_CancelReceive()

491 {

492  USART_DisableReceiveInterrupt();

493  USART_ReceiveBusyFlag = 0;

494 }

495 

501 uint8_t USART_TransmitBlocking(uint8_t *Buffer)

502 {

503  while ((UCSR0A & (1<<UDRE0)) == 0); // Do nothing until UDR is ready

504  UDR0 = *Buffer;

505  return OK;

506 }

507 

514 uint8_t USART_TransmitByte(uint8_t *Buffer)

515 {

516  while (USART_TransmitBusyFlag)

517  {

518  return BUSY;

519  }

520  USART_TransmitBuffer = Buffer;

521  USART_TransmitBufferLength = 1;

522  USART_TransmitBufferIndex = 0;

523  USART_TransmitBusyFlag = 1;

524  USART_EnableTransmitInterrupt();

525  return OK;

526 }

527 

534 uint8_t USART_TransmitTwoBytes(uint16_t *Buffer)

535 {

536  while (USART_TransmitBusyFlag)

537  {

538  return BUSY;

539  }

540  USART_TransmitBuffer = (uint8_t*)Buffer;

541  USART_TransmitBufferLength = 2;

542  USART_TransmitBufferIndex = 0;

543  USART_TransmitBusyFlag = 1;

544  USART_EnableTransmitInterrupt();

545  return OK;

546 }

547 

555 uint8_t USART_TransmitBytes(uint8_t *Buffer, uint16_t Size)

556 {

557  if (Size == 0) return ERROR;

558 

559  while (USART_TransmitBusyFlag)

560  {

561  return BUSY;

562  }

563  USART_TransmitBuffer = Buffer;

564  USART_TransmitBufferLength = Size;

565  USART_TransmitBufferIndex = 0;

566  USART_TransmitBusyFlag = 1;

567  USART_EnableTransmitInterrupt();

568  return OK;

569 }

570 

577 uint8_t USART_TransmitChar(char Character)

578 {

579  uint8_t* data = (uint8_t*)&Character;

580  return USART_TransmitByte(data);

581 }

582 

589 uint8_t USART_TransmitInt(int Number)

590 {

591  while (USART_TransmitBusyFlag)

592  {

593  return BUSY;

594  }

595  static uint8_t localbuffer[7] = {0};

596  uint16_t Length = UTILS_IntToString(Number,(char*)localbuffer);

597  return USART_TransmitBytes(localbuffer,Length);

598 }

599 

606 uint8_t USART_TransmitLong(long Number)

607 {

608  while (USART_TransmitBusyFlag)

609  {

610  return BUSY;

611  }

612  static uint8_t localbuffer[12] = {0};

613  uint16_t Length = UTILS_LongToString(Number,(char*)localbuffer);

614  return USART_TransmitBytes(localbuffer,Length);

615 }

616 

624 uint8_t USART_TransmitFloat(float Number,uint8_t Precision)

625 {

626  while (USART_TransmitBusyFlag)

627  {

628  return BUSY;

629  }

630  static uint8_t localbuffer[17] = {0};

631  uint16_t Length = UTILS_FloatToString(Number,(char*)localbuffer,Precision);

632  return USART_TransmitBytes(localbuffer,Length);

633 }

634 

641 uint8_t USART_TransmitString(char *Buffer)

642 {

643  while (USART_TransmitBusyFlag)

644  {

645  return BUSY;

646  }

647  const char *p = Buffer;

648  while (*p) ++p;

649  uint16_t Size = p - Buffer;

650  USART_TransmitBuffer = (uint8_t*)Buffer;

651  USART_TransmitBufferLength = Size;

652  USART_TransmitBufferIndex = 0;

653  USART_TransmitBusyFlag = 1;

654  USART_EnableTransmitInterrupt();

655  return OK;

656 }

657 

663 void USART_CancelTransmit()

664 {

665  USART_DisableTransmitInterrupt();

666  USART_TransmitBusyFlag = 0;

667 }

668 

674 ISR(USART_RX_vect)

675 {

676  if(USART_ReceiveBufferIndex < USART_ReceiveBufferLength)

677  {

678  USART_ReceiveBuffer[USART_ReceiveBufferIndex] = UDR0;

679  USART_ReceiveBufferIndex++;

680  }

681  if(USART_ReceiveBufferIndex >= USART_ReceiveBufferLength)

682  {

683  USART_ReceiveBusyFlag = 0;

684  USART_DisableReceiveInterrupt();

685  }

686 }

687 

693 ISR(USART_UDRE_vect)

694 {

695  if(USART_TransmitBufferIndex < USART_TransmitBufferLength)

696  {

697  UDR0 = USART_TransmitBuffer[USART_TransmitBufferIndex];

698  USART_TransmitBufferIndex++;

699  }

700  if(USART_TransmitBufferIndex >= USART_TransmitBufferLength)

701  {

702  USART_TransmitBusyFlag = 0;

703  USART_DisableTransmitInterrupt();

704  }

705 }

706 

707 #endif /* AVR_USART_H_ */