2019-08-27 12:14:12 +00:00
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//DingusPPC - Prototype 5bf2
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//Written by divingkatae
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//(c)2018-20 (theweirdo)
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//Please ask for permission
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//if you want to distribute this.
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//(divingkatae#1017 on Discord)
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2019-08-28 00:39:29 +00:00
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/** VIA-CUDA combo device emulation.
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Author: Max Poliakovski 2019
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Versatile interface adapter (VIA) is an old I/O controller that can be found
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in nearly every Macintosh computer. In the 68k era, VIA was used to control
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various peripherial devices. In a Power Macintosh, its function is limited
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to the I/O interface for the Cuda MCU. I therefore decided to put VIA
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emulation code here.
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Cuda MCU is a multipurpose IC built around a custom version of the Motorola
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MC68HC05 microcontroller. It provides several functions including:
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- Apple Desktop Bus (ADB) master
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- I2C bus master
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- Realtime clock (RTC)
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- parameter RAM
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- power management
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MC68HC05 doesn't provide any dedicated hardware for serial communication
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protocols. All signals required for ADB and I2C will be generated by Cuda
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firmware using bit banging (https://en.wikipedia.org/wiki/Bit_banging).
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*/
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2019-08-27 12:14:12 +00:00
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#ifndef VIACUDA_H
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#define VIACUDA_H
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/** VIA register offsets. */
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enum {
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VIA_B = 0x00, /* input/output register B */
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VIA_A = 0x01, /* input/output register A */
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VIA_DIRB = 0x02, /* direction B */
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VIA_DIRA = 0x03, /* direction A */
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VIA_T1CL = 0x04, /* low-order timer 1 counter */
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VIA_T1CH = 0x05, /* high-order timer 1 counter */
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VIA_T1LL = 0x06, /* low-order timer 1 latches */
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VIA_T1LH = 0x07, /* high-order timer 1 latches */
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VIA_T2CL = 0x08, /* low-order timer 2 latches */
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VIA_T2CH = 0x09, /* high-order timer 2 counter */
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VIA_SR = 0x0A, /* shift register */
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VIA_ACR = 0x0B, /* auxiliary control register */
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VIA_PCR = 0x0C, /* periheral control register */
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VIA_IFR = 0x0D, /* interrupt flag register */
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VIA_IER = 0x0E, /* interrupt enable register */
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VIA_ANH = 0x0F, /* input/output register A, no handshake */
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};
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class ViaCuda
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{
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public:
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ViaCuda();
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~ViaCuda() = default;
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uint8_t read(int reg);
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void write(int reg, uint8_t value);
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private:
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uint8_t via_regs[16]; /* VIA virtual registers */
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void print_enabled_ints(); /* print enabled VIA interrupts and their sources */
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};
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#endif /* VIACUDA_H */
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