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Initial implementation of 9bit data support #6443

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69e4683
Initial implementation of 9bit data support
svatoun Jun 30, 2017
7c7d6c3
Removed leftover definition from development
svatoun Jun 30, 2017
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46 changes: 41 additions & 5 deletions hardware/arduino/avr/cores/arduino/HardwareSerial.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -82,9 +82,18 @@ void HardwareSerial::_tx_udr_empty_irq(void)
{
// If interrupts are enabled, there must be more data in the output
// buffer. Send the next byte
unsigned char c = _tx_buffer[_tx_buffer_tail];
serial_data_t c = _tx_buffer[_tx_buffer_tail];
_tx_buffer_tail = (_tx_buffer_tail + 1) % SERIAL_TX_BUFFER_SIZE;

#ifdef SERIAL9
if (use9bit) {
if (c & 0x100) {
sbi(*_ucsrb, TXB80);
} else {
cbi(*_ucsrb, TXB80);
}
c = c & 0xff;
}
#endif // SERIAL9
*_udr = c;

// clear the TXC bit -- "can be cleared by writing a one to its bit
Expand All @@ -100,8 +109,9 @@ void HardwareSerial::_tx_udr_empty_irq(void)

// Public Methods //////////////////////////////////////////////////////////////

void HardwareSerial::begin(unsigned long baud, byte config)
void HardwareSerial::begin(unsigned long baud, uint16_t extConfig)
{
byte config = extConfig & 0xff;
// Try u2x mode first
uint16_t baud_setting = (F_CPU / 4 / baud - 1) / 2;
*_ucsra = 1 << U2X0;
Expand All @@ -128,7 +138,15 @@ void HardwareSerial::begin(unsigned long baud, byte config)
config |= 0x80; // select UCSRC register (shared with UBRRH)
#endif
*_ucsrc = config;

#ifdef SERIAL9
if (extConfig & 0x100) {
sbi(*_ucsrb, UCSZ02);
use9bit = true;
} else {
use9bit = false;
}
#endif // SERIAL9

sbi(*_ucsrb, RXEN0);
sbi(*_ucsrb, TXEN0);
sbi(*_ucsrb, RXCIE0);
Expand Down Expand Up @@ -169,7 +187,7 @@ int HardwareSerial::read(void)
if (_rx_buffer_head == _rx_buffer_tail) {
return -1;
} else {
unsigned char c = _rx_buffer[_rx_buffer_tail];
serial_data_t c = _rx_buffer[_rx_buffer_tail];
_rx_buffer_tail = (rx_buffer_index_t)(_rx_buffer_tail + 1) % SERIAL_RX_BUFFER_SIZE;
return c;
}
Expand Down Expand Up @@ -210,14 +228,28 @@ void HardwareSerial::flush()
// the hardware finished tranmission (TXC is set).
}

#ifdef SERIAL9
size_t HardwareSerial::write9(uint16_t c)
#else // !defined(SERIAL9)
size_t HardwareSerial::write(uint8_t c)
#endif // SERIAL9
{
_written = true;
// If the buffer and the data register is empty, just write the byte
// to the data register and be done. This shortcut helps
// significantly improve the effective datarate at high (>
// 500kbit/s) bitrates, where interrupt overhead becomes a slowdown.
if (_tx_buffer_head == _tx_buffer_tail && bit_is_set(*_ucsra, UDRE0)) {
#ifdef SERIAL9
if (use9bit) {
if (c & 0x100) {
sbi(*_ucsrb, TXB80);
} else {
cbi(*_ucsrb, TXB80);
}
c = c & 0xff;
}
#endif // SERIAL9
*_udr = c;
sbi(*_ucsra, TXC0);
return 1;
Expand All @@ -239,7 +271,11 @@ size_t HardwareSerial::write(uint8_t c)
}
}

#ifdef SERIAL9
_tx_buffer[_tx_buffer_head] = (c & 0x1ff);
#else // !defined(SERIAL9)
_tx_buffer[_tx_buffer_head] = c;
#endif // SERIAL9
_tx_buffer_head = i;

sbi(*_ucsrb, UDRIE0);
Expand Down
36 changes: 32 additions & 4 deletions hardware/arduino/avr/cores/arduino/HardwareSerial.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,12 @@ typedef uint16_t rx_buffer_index_t;
typedef uint8_t rx_buffer_index_t;
#endif

#ifdef SERIAL9
typedef unsigned short serial_data_t;
#else
typedef unsigned char serial_data_t;
#endif // SERIAL9

// Define config for Serial.begin(baud, config);
#define SERIAL_5N1 0x00
#define SERIAL_6N1 0x02
Expand All @@ -90,6 +96,17 @@ typedef uint8_t rx_buffer_index_t;
#define SERIAL_7O2 0x3C
#define SERIAL_8O2 0x3E

#ifdef SERIAL9

#define SERIAL_9N1 0x106
#define SERIAL_9N2 (0x106 + SERIAL_5N2)
#define SERIAL_9E1 (0x106 + SERIAL_5E1)
#define SERIAL_9E2 (0x106 + SERIAL_5E2)
#define SERIAL_9O1 (0x106 + SERIAL_5O1)
#define SERIAL_9O2 (0x106 + SERIAL_5O2)

#endif // SERIAL9

class HardwareSerial : public Stream
{
protected:
Expand All @@ -101,6 +118,9 @@ class HardwareSerial : public Stream
volatile uint8_t * const _udr;
// Has any byte been written to the UART since begin()
bool _written;
#ifdef SERIAL9
volatile bool use9bit;
#endif // SERIAL9

volatile rx_buffer_index_t _rx_buffer_head;
volatile rx_buffer_index_t _rx_buffer_tail;
Expand All @@ -110,27 +130,35 @@ class HardwareSerial : public Stream
// Don't put any members after these buffers, since only the first
// 32 bytes of this struct can be accessed quickly using the ldd
// instruction.
unsigned char _rx_buffer[SERIAL_RX_BUFFER_SIZE];
unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE];
serial_data_t _rx_buffer[SERIAL_RX_BUFFER_SIZE];
serial_data_t _tx_buffer[SERIAL_TX_BUFFER_SIZE];

public:
inline HardwareSerial(
volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
volatile uint8_t *ucsrc, volatile uint8_t *udr);
void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }
void begin(unsigned long, uint8_t);
void begin(unsigned long, uint16_t);
void end();
virtual int available(void);
virtual int peek(void);
virtual int read(void);
virtual int availableForWrite(void);
virtual void flush(void);
virtual size_t write(uint8_t);
inline size_t write(unsigned long n) { return write((uint8_t)n); }
inline size_t write(long n) { return write((uint8_t)n); }
inline size_t write(unsigned int n) { return write((uint8_t)n); }
inline size_t write(int n) { return write((uint8_t)n); }

#ifdef SERIAL9
size_t write9(unsigned int);
inline size_t write9(long n) { return write9((unsigned int)n); }
inline size_t write9(int n) { return write9((unsigned int)n); }
inline size_t write(uint8_t n) { return write9((unsigned int)n); }
#else // !defined(SERIAL9)
virtual size_t write(uint8_t);
#endif // SERIAL9
using Print::write; // pull in write(str) and write(buf, size) from Print
operator bool() { return true; }

Expand Down
13 changes: 12 additions & 1 deletion hardware/arduino/avr/cores/arduino/HardwareSerial_private.h
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Original file line number Diff line number Diff line change
Expand Up @@ -93,6 +93,9 @@ HardwareSerial::HardwareSerial(
_udr(udr),
_rx_buffer_head(0), _rx_buffer_tail(0),
_tx_buffer_head(0), _tx_buffer_tail(0)
#ifdef SERIAL9
,use9bit(false)
#endif // SERIAL9
{
}

Expand All @@ -103,7 +106,15 @@ void HardwareSerial::_rx_complete_irq(void)
if (bit_is_clear(*_ucsra, UPE0)) {
// No Parity error, read byte and store it in the buffer if there is
// room
unsigned char c = *_udr;
serial_data_t c = 0;
#ifdef SERIAL9
if (use9bit) {
if (bit_is_set(*_ucsrb, RXB80)) {
c = 0x100;
}
}
#endif // SERIAL9
c |= *_udr;
rx_buffer_index_t i = (unsigned int)(_rx_buffer_head + 1) % SERIAL_RX_BUFFER_SIZE;

// if we should be storing the received character into the location
Expand Down