// license:BSD-3-Clause
// copyright-holders:Curt Coder
/**********************************************************************
MM74C922/MM74C923 16/20-Key Encoder emulation
**********************************************************************
_____ _____
ROW Y1 1 |* \_/ | 18 Vcc
ROW Y2 2 | | 17 DATA OUT A
ROW Y3 3 | | 16 DATA OUT B
ROW Y4 4 | | 15 DATA OUT C
OSCILLATOR 5 | MM74C922 | 14 DATA OUT D
KEYBOUNCE MASK 6 | | 13 _OUTPUT ENABLE
COLUMN X4 7 | | 12 DATA AVAILABLE
COLUMN X3 8 | | 11 COLUMN X1
GND 9 |_____________| 10 COLUMN X2
_____ _____
ROW Y1 1 |* \_/ | 20 Vcc
ROW Y2 2 | | 19 DATA OUT A
ROW Y3 3 | | 18 DATA OUT B
ROW Y4 4 | | 17 DATA OUT C
ROW Y5 5 | MM74C923 | 16 DATA OUT D
OSCILLATOR 6 | | 15 DATA OUT E
KEYBOUNCE MASK 7 | | 14 _OUTPUT ENABLE
COLUMN X4 8 | | 13 DATA AVAILABLE
COLUMN X3 9 | | 12 COLUMN X1
GND 10 |_____________| 11 COLUMN X2
**********************************************************************/
#pragma once
#ifndef __MM74C922__
#define __MM74C922__
#include "emu.h"
//**************************************************************************
// INTERFACE CONFIGURATION MACROS
//**************************************************************************
#define MCFG_MM74C922_OSC(_value) \
mm74c922_device::static_set_cap_osc(*device, _value);
#define MCFG_MM74C922_DEBOUNCE(_value) \
mm74c922_device::static_set_cap_debounce(*device, _value);
#define MCFG_MM74C922_DA_CALLBACK(_write) \
devcb = &mm74c922_device::set_da_wr_callback(*device, DEVCB_##_write);
#define MCFG_MM74C922_X1_CALLBACK(_read) \
devcb = &mm74c922_device::set_x1_rd_callback(*device, DEVCB_##_read);
#define MCFG_MM74C922_X2_CALLBACK(_read) \
devcb = &mm74c922_device::set_x2_rd_callback(*device, DEVCB_##_read);
#define MCFG_MM74C922_X3_CALLBACK(_read) \
devcb = &mm74c922_device::set_x3_rd_callback(*device, DEVCB_##_read);
#define MCFG_MM74C922_X4_CALLBACK(_read) \
devcb = &mm74c922_device::set_x4_rd_callback(*device, DEVCB_##_read);
#define MCFG_MM74C922_X5_CALLBACK(_read) \
devcb = &mm74c922_device::set_x5_rd_callback(*device, DEVCB_##_read);
//**************************************************************************
// TYPE DEFINITIONS
//**************************************************************************
// ======================> mm74c922_device
class mm74c922_device : public device_t
{
public:
// construction/destruction
mm74c922_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
static void static_set_cap_osc(device_t &device, double value) { downcast<mm74c922_device &>(device).m_cap_osc = value; }
static void static_set_cap_debounce(device_t &device, double value) { downcast<mm74c922_device &>(device).m_cap_debounce = value; }
template<class _Object> static devcb_base &set_da_wr_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_write_da.set_callback(object); }
template<class _Object> static devcb_base &set_x1_rd_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_read_x1.set_callback(object); }
template<class _Object> static devcb_base &set_x2_rd_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_read_x2.set_callback(object); }
template<class _Object> static devcb_base &set_x3_rd_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_read_x3.set_callback(object); }
template<class _Object> static devcb_base &set_x4_rd_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_read_x4.set_callback(object); }
template<class _Object> static devcb_base &set_x5_rd_callback(device_t &device, _Object object) { return downcast<mm74c922_device &>(device).m_read_x5.set_callback(object); }
UINT8 read();
protected:
// device-level overrides
virtual void device_start() override;
virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
private:
void change_output_lines();
void clock_scan_counters();
void detect_keypress();
devcb_write_line m_write_da;
devcb_read8 m_read_x1;
devcb_read8 m_read_x2;
devcb_read8 m_read_x3;
devcb_read8 m_read_x4;
devcb_read8 m_read_x5;
double m_cap_osc;
double m_cap_debounce;
int m_max_y;
int m_inhibit; // scan counter clock inhibit
int m_x; // currently scanned column
int m_y; // latched row
UINT8 m_data; // data latch
int m_da; // data available flag
int m_next_da; // next value of data available flag
// timers
emu_timer *m_scan_timer; // keyboard scan timer
};
// device type definition
extern const device_type MM74C922;
extern const device_type MM74C923;
#endif