b15f/firmware/usart.cpp
Tristan Krause b6d0b4c8f5 rename
2019-04-01 15:16:47 +02:00

131 lines
2.1 KiB
C++

#include "usart.h"
void USART::init()
{
UCSR0A = _BV(U2X0);
UCSR0B = _BV(RXEN0) | _BV(TXEN0);
// Einstellen des Datenformats: 8 Datenbits, 1 Stoppbit
UCSR0C = _BV(UCSZ00) |_BV(UCSZ01);// (1<<URSEL0)|(1<<UCSZ10)|(1<<UCSZ00);
// setze Baudrate
UBRR0H = (((F_CPU / (8UL * BAUDRATE))-1) >> 8) & 0xFF;
UBRR0L = ((F_CPU / (8UL * BAUDRATE))-1) & 0xFF;
}
void USART::flush()
{
uint8_t dummy;
do
{
dummy = UDR0;
_delay_us((1000000 / BAUDRATE) * 16); // Warte Übertragungszeit von 16 Bit ab
}
while (UCSR0A & (1<<RXC0));
if(dummy) // taeusche dummy Verwendung vor
return;
}
void USART::writeByte(uint8_t b)
{
while (!(UCSR0A & (1<<UDRE0)));
UDR0 = b;
//while(!(UCSR0A & _BV(TXC0)));
}
void USART::writeInt(uint16_t v)
{
while (!(UCSR0A & (1<<UDRE0)));
UDR0 = v & 0xFF;
v >>= 8;
while (!(UCSR0A & (1<<UDRE0)));
UDR0 = v & 0xFF;
//while(!(UCSR0A & _BV(TXC0)));
}
void USART::writeStr(const char* str, uint8_t len)
{
writeByte(len);
while(len--)
writeByte(*str++);
}
uint8_t USART::writeBlock(uint8_t* ptr, uint8_t len)
{
writeByte(len);
uint8_t crc = 0;
while(len--)
{
writeByte(*ptr);
crc ^= *ptr++;
for (uint8_t i = 0; i < 8; i++)
{
if (crc & 1)
crc ^= CRC7_POLY;
crc >>= 1;
}
}
writeByte(crc);
return readByte();
}
uint8_t USART::readByte()
{
while (!(UCSR0A & (1<<RXC0)));
return UDR0;
}
uint16_t USART::readInt()
{
uint16_t v = readByte();
v |= readByte() << 8;
return v;
}
void USART::readBlock(uint8_t* ptr, uint8_t offset)
{
ptr += offset;
uint8_t crc;
do
{
crc = 0;
uint8_t len = readByte();
if(len > MAX_BLOCK_SIZE)
len = 0;
for(uint8_t k = 0; k <= len; k++) // len + 1 Durchgänge (+ crc)
{
uint8_t next = readByte();
crc ^= next;
for (uint8_t i = 0; i < 8; i++)
{
if (crc & 1)
crc ^= CRC7_POLY;
crc >>= 1;
}
if(k < len)
ptr[k] = next;
}
flush(); // leere Eingangspuffer
writeByte(crc == 0 ? MSG_OK : MSG_FAIL);
}
while(crc != 0);
}