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Enable interrupt mode of UART tx #266

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Merged
merged 1 commit into from
Nov 29, 2016
Merged

Enable interrupt mode of UART tx #266

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37 changes: 22 additions & 15 deletions cores/arduino/UARTClass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -168,7 +168,7 @@ int UARTClass::read( void )

void UARTClass::flush( void )
{
while (_tx_buffer->_iHead != _tx_buffer->_iTail); //wait for transmit data to be sent
while (_tx_buffer->_iHead != *(volatile int*)&(_tx_buffer->_iTail)); //wait for transmit data to be sent
// Wait for transmission to complete
while(!uart_tx_complete(CONFIG_UART_CONSOLE_INDEX));
}
Expand All @@ -179,12 +179,11 @@ size_t UARTClass::write( const uint8_t uc_data )
return(0);

// Is the hardware currently busy?
if (_tx_buffer->_iTail != _tx_buffer->_iHead)
if (_tx_buffer->_iTail != _tx_buffer->_iHead || !uart_tx_ready(CONFIG_UART_CONSOLE_INDEX))
{
// If busy we buffer
int l = (_tx_buffer->_iHead + 1) % UART_BUFFER_SIZE;
while (_tx_buffer->_iTail == l)
; // Spin locks if we're about to overwrite the buffer. This continues once the data is sent
while (*(volatile int*)&(_tx_buffer->_iTail) == l); // Spin locks if we're about to overwrite the buffer. This continues once the data is sent

_tx_buffer->_aucBuffer[_tx_buffer->_iHead] = uc_data;
_tx_buffer->_iHead = l;
Expand All @@ -201,21 +200,29 @@ size_t UARTClass::write( const uint8_t uc_data )

void UARTClass::IrqHandler( void )
{
uint8_t uc_data;
int ret;
ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);

while ( ret != -1 ) {
_rx_buffer->store_char(uc_data);
uart_irq_update(CONFIG_UART_CONSOLE_INDEX);
// if irq is Receiver Data Available
if(uart_irq_rx_ready(CONFIG_UART_CONSOLE_INDEX))
{
uint8_t uc_data;
int ret;
ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);

while ( ret != -1 ) {
_rx_buffer->store_char(uc_data);
ret = uart_poll_in(CONFIG_UART_CONSOLE_INDEX, &uc_data);
}
}

// Do we need to keep sending data?
if (!uart_irq_tx_ready(CONFIG_UART_CONSOLE_INDEX))
// if irq is Transmitter Holding Register
else if(uart_irq_tx_ready(CONFIG_UART_CONSOLE_INDEX))
{
if (_tx_buffer->_iTail != _tx_buffer->_iHead) {
uart_poll_out(CONFIG_UART_CONSOLE_INDEX, _tx_buffer->_aucBuffer[_tx_buffer->_iTail]);
_tx_buffer->_iTail = (unsigned int)(_tx_buffer->_iTail + 1) % UART_BUFFER_SIZE;
if(_tx_buffer->_iTail != _tx_buffer->_iHead)
{
int end = (_tx_buffer->_iTail < _tx_buffer->_iHead) ? _tx_buffer->_iHead:UART_BUFFER_SIZE;
int l = min(end - _tx_buffer->_iTail, UART_FIFO_SIZE);
uart_fifo_fill(CONFIG_UART_CONSOLE_INDEX, _tx_buffer->_aucBuffer+_tx_buffer->_iTail, l);
_tx_buffer->_iTail = (_tx_buffer->_iTail+l)%UART_BUFFER_SIZE;
}
else
{
Expand Down
21 changes: 18 additions & 3 deletions system/libarc32_arduino101/drivers/ns16550.c
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Original file line number Diff line number Diff line change
Expand Up @@ -340,7 +340,7 @@ unsigned char uart_poll_out(
)
{
/* wait for transmitter to ready to accept a character */
while ((INBYTE(LSR(which)) & LSR_TEMT) == 0)
while ((INBYTE(LSR(which)) & LSR_THRE) == 0)
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Why is TEMT not sufficient? With our UART configuration it should be set when both THR and FIFO are empty, right?

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Nevermind, you're right, TEMT is set when THR and TSR are empty. Since uart_poll_out only places a byte in THR, then THRE is sufficient.

;

OUTBYTE(THR(which), outChar);
Expand All @@ -352,6 +352,8 @@ unsigned char uart_poll_out(
*
* uart_fifo_fill - fill FIFO with data
*
* It is up to the caller to make sure that FIFO capcity is not exceeded
*
* RETURNS: number of bytes sent
*/

Expand All @@ -362,8 +364,8 @@ int uart_fifo_fill(int which, /* UART on which to send */
{
int i;

for (i = 0; i < size && (INBYTE(LSR(which)) &
LSR_BOTH_EMPTY) != 0; i++) {
for (i = 0; i < size ; i++)
{
OUTBYTE(THR(which), txData[i]);
}
return i;
Expand Down Expand Up @@ -640,6 +642,19 @@ uint8_t uart_tx_complete(int which)
return INBYTE(LSR(which)) & LSR_TEMT;
}

/*******************************************************************************
*
* uart_tx_complete - check if tx holding register is empty
*
* RETURNS: zero if register is non-empty,
* non-zero if register is empty (ready to receive new data)
*/

uint8_t uart_tx_ready(int which)
{
return INBYTE(LSR(which)) & LSR_THRE;
}

/*******************************************************************************
*
* uart_loop_enable - enable loopback
Expand Down
4 changes: 4 additions & 0 deletions system/libarc32_arduino101/drivers/uart.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,9 @@ extern "C" {
/* options for uart init */
#define UART_OPTION_AFCE 0x01

/* Size of the FIFO in bytes */
#define UART_FIFO_SIZE 16

/* generic UART info structure */
struct uart_init_info {
int baud_rate;
Expand Down Expand Up @@ -92,6 +95,7 @@ int uart_break_check(int port);
void uart_break_send(int port, int delay);
void uart_disable(int port);
uint8_t uart_tx_complete(int which);
uint8_t uart_tx_ready(int which);
void uart_loop_enable(int which);
void uart_loop_disable(int which);

Expand Down
Binary file modified variants/arduino_101/libarc32drv_arduino101.a
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