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author | Nao Pross <naopross@thearcway.org> | 2018-10-30 11:41:24 +0100 |
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committer | Nao Pross <naopross@thearcway.org> | 2018-10-30 11:41:24 +0100 |
commit | 43be150dc6e84f6f6eeb071cd3cdb7fc21125d60 (patch) | |
tree | 541fd3d690c1bdfd7b68d684029a400b80f4aa06 /sw-old/z80/drivers/usart.c | |
parent | Add datasheets for ATmega328 and 74LS259 (diff) | |
download | z80uPC-43be150dc6e84f6f6eeb071cd3cdb7fc21125d60.tar.gz z80uPC-43be150dc6e84f6f6eeb071cd3cdb7fc21125d60.zip |
Move sw to sw-old and hw to hw-altium, add kicad files
Diffstat (limited to 'sw-old/z80/drivers/usart.c')
-rw-r--r-- | sw-old/z80/drivers/usart.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/sw-old/z80/drivers/usart.c b/sw-old/z80/drivers/usart.c new file mode 100644 index 0000000..9a5ee38 --- /dev/null +++ b/sw-old/z80/drivers/usart.c @@ -0,0 +1,91 @@ +#include "usart.h" + +static volatile struct _usart_device *_usart = ((struct _usart_device *) ADDR_DEV_USART); + +void usart_set_baudrate(uint16_t baudrate) +{ + // enable latch access + _usart->LCR.divisor_latch_access = 1; + _usart->buffer = 0x00FF & baudrate; // LSBs + memcpy(&_usart->IER, &(baudrate >>8), 1); + // _usart->IER = 0x00FF & (baudrate >> 8); // MSBs + _usart->LCR.divisor_latch_access = 0; +} + +void usart_set_parity(int mode) +{ + if (mode == USART_PARITY_EVEN) { + _usart->LCR.even_parity = 1; + } + else if (mode == USART_PARITY_ODD) { + _usart->LCR.even_parity = 0; + } + + _usart->LCR.parity = (mode == USART_PARITY_NONE) ? 0 : 1; +} + +void usart_set_stop_bits(int count) +{ + _usart->LCR.stop_bits = (count == USART_STOP_BITS_1) ? 0 : 1; +} + +void usart_word_length(int length) +{ + _usart->LCR.word_length = length; +} + +void usart_set_autoflow(int mode) +{ + _usart->MCR.autoflow = (mode == USART_AUTOFLOW_OFF) ? 0 : 1; + _usart->MCR.data_terminal_ready = (mode == USART_AUTOFLOW_ALL); +} + +inline void usart_init(uint16_t baudrate, int parity, int stop_bits) +{ + usart_set_baudrate(baudrate); + usart_set_parity(parity); + usart_set_stop_bits(stop_bits); + usart_set_autoflow(USART_AUTOFLOW_OFF); +} + +void usart_transmit(uint8_t data) +{ + _usart->buffer = data; + while (_usart->LSR.transmitter_holder_empty == 0); // wait +} + +uint8_t usart_receive() +{ + return _usart->buffer; +} + +int usart_write(uint8_t *data, size_t size) +{ + uint8_t *dp = data; + + while (size--) { + _usart->buffer = *(dp++); + while (_usart->LSR.transmitter_empty); + } + + // TODO: do something that actually counts for sent bytes + return size; +} + +int usart_read(uint8_t *buffer, size_t count) +{ + uint8_t *bp = buffer; + size_t read_count = 0; + + while (count--) { + *(bp++) = _usart->buffer; + // check for errors + if (_usart->LSR.framing_error || _usart->LSR.parity_error) { + bp--; // delete last byte (?) + } else { + read_count++; + } + } + + return read_count; +} |