libopencm3/lib/usart.c

121 lines
2.7 KiB
C

/*
* This file is part of the libopenstm32 project.
*
* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libopenstm32/usart.h>
void usart_set_baudrate(u32 usart, u32 baud)
{
u32 clock = 72000000; /* FIXME: Don't hardcode this clock! */
/* TODO: Document and explain calculation. */
USART_BRR(usart) = (u16)((clock << 4) / (baud * 16));
}
void usart_set_databits(u32 usart, u32 bits)
{
if (bits == 8)
USART_CR1(usart) &= ~USART_CR1_M; /* 8 data bits */
else
USART_CR1(usart) |= USART_CR1_M; /* 9 data bits */
}
void usart_set_stopbits(u32 usart, u32 stopbits)
{
u32 reg32;
reg32 = USART_CR2(usart);
reg32 = (reg32 & ~USART_CR2_STOPBITS_MASK) | stopbits;
USART_CR2(usart) = reg32;
}
void usart_set_parity(u32 usart, u32 parity)
{
u32 reg32;
reg32 = USART_CR1(usart);
reg32 = (reg32 & ~USART_PARITY_MASK) | parity;
USART_CR1(usart) = reg32;
}
void usart_set_mode(u32 usart, u32 mode)
{
u32 reg32;
reg32 = USART_CR1(usart);
reg32 = (reg32 & ~USART_MODE_MASK) | mode;
USART_CR1(usart) = reg32;
}
void usart_set_flow_control(u32 usart, u32 flowcontrol)
{
u32 reg32;
reg32 = USART_CR3(usart);
reg32 = (reg32 & ~USART_FLOWCONTROL_MASK) | flowcontrol;
USART_CR3(usart) = reg32;
}
void usart_enable(u32 usart)
{
USART_CR1(usart) |= USART_CR1_UE;
}
void usart_disable(u32 usart)
{
USART_CR1(usart) &= ~USART_CR1_UE;
}
void usart_send(u32 usart, u16 data)
{
/* Send data. */
USART_DR(usart) = (data & USART_DR_MASK);
}
u16 usart_recv(u32 usart)
{
/* Receive data. */
return USART_DR(usart) & USART_DR_MASK;
}
void usart_wait_send_ready(u32 usart)
{
/* Wait until the data has been transferred into the shift register. */
while ((USART_SR(usart) & USART_SR_TXE) == 0);
}
void usart_wait_recv_ready(u32 usart)
{
/* Wait until the data is ready to be received. */
while ((USART_SR(usart) & USART_SR_RXNE) == 0);
}
void usart_send_blocking(u32 usart, u16 data)
{
usart_send(usart, data);
usart_wait_send_ready(usart);
}
u16 usart_recv_blocking(u32 usart)
{
usart_wait_recv_ready(usart);
return usart_recv(usart);
}