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40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
#include <stdint.h>
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#include <stdbool.h>
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typedef struct {
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// Bit 7: interrupt status, low when interrupt request pending.
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// Bit 6: Parity error
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// Bit 5: Receiver overrun
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// Bit 4: Framing error
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// Bit 3: Clear To Send
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// Bit 2: Data Carrier Detected
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// Bit 1: Transmit Data Register Empty (TDRE)
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// Bit 0: Receive Data Register Full (RDRF)
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// We care about bits 7, 1, 0, maybe 5 later.
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uint8_t status;
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// Bit 7: interrupt enable
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// Bits 6:5: RTS + transmit interrupt enable
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// Bits 4:2: parity + stop bit
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// Bits 1:0: speed divider
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// We don't actually care about any of those except the interrupt enable
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// bits.
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uint8_t control;
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uint8_t rx;
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uint8_t tx;
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// Will be set to true the first time acia_has_irq() is called when IRQ is
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// set. Then, as long as it stays true, acia_has_irq() will return false.
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// When IRQ status is reset, so is in_int.
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bool in_int;
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} ACIA;
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void acia_init(ACIA *acia);
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bool acia_has_irq(ACIA *acia);
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bool acia_hasrx(ACIA *acia);
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bool acia_hastx(ACIA *acia);
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uint8_t acia_read(ACIA *acia);
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void acia_write(ACIA *acia, uint8_t val);
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uint8_t acia_ctl_rd(ACIA *acia);
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void acia_ctl_wr(ACIA *acia, uint8_t val);
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uint8_t acia_data_rd(ACIA *acia);
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void acia_data_wr(ACIA *acia, uint8_t val);
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