88 lines
2.1 KiB
C#
88 lines
2.1 KiB
C#
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namespace PIC_Simulator.PIC
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{
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class PICTimer
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{
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private PICProgramm programm;
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public PICTimer(PICProgramm p)
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{
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programm = p;
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}
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private bool prev_RA4 = false;
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public void TimerBerechnen(uint cycles)
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{
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bool tmr_mode = programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_T0CS);
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bool edge_mode = programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_T0SE);
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if (!tmr_mode)
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{
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bool curr_A4 = programm.GetRegisterOhneBank(PICProgramm.ADDR_PORT_A, 4);
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if (edge_mode)
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{
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if (prev_RA4 && !curr_A4)
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{
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TimerHochzaehlen(cycles);
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}
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}
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else
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{
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if (!prev_RA4 && curr_A4)
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{
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TimerHochzaehlen(cycles);
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}
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}
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}
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else
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{
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TimerHochzaehlen(cycles);
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}
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prev_RA4 = programm.GetRegisterOhneBank(PICProgramm.ADDR_PORT_A, 4);
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}
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private uint prescale_cntr = 0; // Zähler für timer
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private void TimerHochzaehlen(uint cycles)
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{
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uint current = programm.GetRegisterOhneBank(PICProgramm.ADDR_TMR0);
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uint scale = BerechneVorskalierung();
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prescale_cntr += cycles;
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while (prescale_cntr >= scale)
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{
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prescale_cntr -= scale;
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uint Result = current + 1;
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if (Result > 0xFF)
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{
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programm.TimerInterrupt();
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}
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Result %= 0x100;
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uint tmp_psc = prescale_cntr;
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programm.SetRegisterOhneBank(PICProgramm.ADDR_TMR0, Result);
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prescale_cntr = tmp_psc;
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}
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}
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private uint BerechneVorskalierung()
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{
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bool prescale_mode = programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_PSA);
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uint scale = 0;
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scale += programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_PS2) ? 1U : 0U;
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scale *= 2;
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scale += programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_PS1) ? 1U : 0U;
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scale *= 2;
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scale += programm.GetRegisterOhneBank(PICProgramm.ADDR_OPTION, PICProgramm.OPTION_BIT_PS0) ? 1U : 0U;
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return prescale_mode ? 1 : (PICProgramm.SHL(2, scale));
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}
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}
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}
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