mirror of
https://github.com/dingusdev/dingusppc.git
synced 2024-12-23 21:29:28 +00:00
124 lines
4.0 KiB
C++
124 lines
4.0 KiB
C++
//DingusPPC - Prototype 5bf2
|
|
//Written by divingkatae
|
|
//(c)2018-20 (theweirdo)
|
|
//Please ask for permission
|
|
//if you want to distribute this.
|
|
//(divingkatae#1017 on Discord)
|
|
|
|
/** VIA-CUDA combo device emulation.
|
|
|
|
Author: Max Poliakovski 2019
|
|
|
|
Versatile interface adapter (VIA) is an old I/O controller that can be found
|
|
in nearly every Macintosh computer. In the 68k era, VIA was used to control
|
|
various peripherial devices. In a Power Macintosh, its function is limited
|
|
to the I/O interface for the Cuda MCU. I therefore decided to put VIA
|
|
emulation code here.
|
|
|
|
Cuda MCU is a multipurpose IC built around a custom version of the Motorola
|
|
MC68HC05 microcontroller. It provides several functions including:
|
|
- Apple Desktop Bus (ADB) master
|
|
- I2C bus master
|
|
- Realtime clock (RTC)
|
|
- parameter RAM (first generation of the Power Macintosh)
|
|
- power management
|
|
|
|
MC68HC05 doesn't provide any dedicated hardware for serial communication
|
|
protocols. All signals required for ADB and I2C will be generated by Cuda
|
|
firmware using bit banging (https://en.wikipedia.org/wiki/Bit_banging).
|
|
*/
|
|
|
|
#ifndef VIACUDA_H
|
|
#define VIACUDA_H
|
|
|
|
/** VIA register offsets. */
|
|
enum {
|
|
VIA_B = 0x00, /* input/output register B */
|
|
VIA_A = 0x01, /* input/output register A */
|
|
VIA_DIRB = 0x02, /* direction B */
|
|
VIA_DIRA = 0x03, /* direction A */
|
|
VIA_T1CL = 0x04, /* low-order timer 1 counter */
|
|
VIA_T1CH = 0x05, /* high-order timer 1 counter */
|
|
VIA_T1LL = 0x06, /* low-order timer 1 latches */
|
|
VIA_T1LH = 0x07, /* high-order timer 1 latches */
|
|
VIA_T2CL = 0x08, /* low-order timer 2 latches */
|
|
VIA_T2CH = 0x09, /* high-order timer 2 counter */
|
|
VIA_SR = 0x0A, /* shift register */
|
|
VIA_ACR = 0x0B, /* auxiliary control register */
|
|
VIA_PCR = 0x0C, /* periheral control register */
|
|
VIA_IFR = 0x0D, /* interrupt flag register */
|
|
VIA_IER = 0x0E, /* interrupt enable register */
|
|
VIA_ANH = 0x0F, /* input/output register A, no handshake */
|
|
};
|
|
|
|
/** Cuda communication signals. */
|
|
enum {
|
|
CUDA_TIP = 0x20, /* transaction in progress: 0 - true, 1 - false */
|
|
CUDA_BYTEACK = 0x10, /* byte acknowledge: 0 - true, 1 - false */
|
|
CUDA_TREQ = 0x08 /* Cuda requests transaction from host */
|
|
};
|
|
|
|
/** Cuda packet types. */
|
|
enum {
|
|
CUDA_PKT_ADB = 0,
|
|
CUDA_PKT_PSEUDO = 1,
|
|
CUDA_PKT_ERROR = 2,
|
|
CUDA_PKT_TICK = 3,
|
|
CUDA_PKT_POWER = 4
|
|
};
|
|
|
|
/** Cuda pseudo commands. */
|
|
enum {
|
|
CUDA_READ_WRITE_I2C = 0x22, /* read/write I2C device */
|
|
CUDA_COMB_FMT_I2C = 0x25, /* combined format I2C transaction */
|
|
CUDA_OUT_PB0 = 0x26, /* output one bit to Cuda's PB0 line */
|
|
};
|
|
|
|
/** Cuda error codes. */
|
|
enum {
|
|
CUDA_ERR_BAD_CMD = 2, /* invalid pseudo command */
|
|
CUDA_ERR_I2C = 5 /* invalid I2C data or no acknowledge */
|
|
};
|
|
|
|
|
|
class ViaCuda
|
|
{
|
|
public:
|
|
ViaCuda();
|
|
~ViaCuda() = default;
|
|
|
|
uint8_t read(int reg);
|
|
void write(int reg, uint8_t value);
|
|
|
|
private:
|
|
uint8_t via_regs[16]; /* VIA virtual registers */
|
|
|
|
/* Cuda state. */
|
|
uint8_t old_tip;
|
|
uint8_t old_byteack;
|
|
uint8_t treq;
|
|
uint8_t in_buf[16];
|
|
int32_t in_count;
|
|
uint8_t out_buf[16];
|
|
int32_t out_count;
|
|
int32_t out_pos;
|
|
|
|
void print_enabled_ints(); /* print enabled VIA interrupts and their sources */
|
|
|
|
void cuda_init();
|
|
bool cuda_ready();
|
|
void assert_sr_int();
|
|
void cuda_write(uint8_t new_state);
|
|
void cuda_response_header(uint32_t pkt_type, uint32_t pkt_flag);
|
|
void cuda_error_response(uint32_t error);
|
|
void cuda_process_packet();
|
|
void cuda_pseudo_command(int cmd, int data_count);
|
|
|
|
/* I2C related methods */
|
|
void i2c_simple_transaction(uint8_t dev_addr, const uint8_t *in_buf, int in_bytes);
|
|
void i2c_comb_transaction(uint8_t dev_addr, uint8_t sub_addr, uint8_t dev_addr1,
|
|
const uint8_t *in_buf, int in_bytes);
|
|
};
|
|
|
|
#endif /* VIACUDA_H */
|