// 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 **********************************************************************/ #ifndef MAME_MACHINE_MM74C922_H #define MAME_MACHINE_MM74C922_H #pragma once //************************************************************************** // 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_t clock); void set_cap_osc(double value) { m_cap_osc = value; } void set_cap_debounce(double value) { m_cap_debounce = value; } auto da_wr_callback() { return m_write_da.bind(); } auto x1_rd_callback() { return m_read_x[0].bind(); } auto x2_rd_callback() { return m_read_x[1].bind(); } auto x3_rd_callback() { return m_read_x[2].bind(); } auto x4_rd_callback() { return m_read_x[3].bind(); } uint8_t read(); DECLARE_READ_LINE_MEMBER(da_r) { return m_da; } protected: mm74c922_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock, int max_y); // 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_x[4]; double m_cap_osc; double m_cap_debounce; const int m_max_y; bool m_inhibit; // scan counter clock inhibit int m_x; // currently scanned column int m_y; // latched row uint8_t m_data; // data latch bool m_da; // data available flag bool m_next_da; // next value of data available flag // timers emu_timer *m_scan_timer; // keyboard scan timer }; // ======================> mm74c923_device class mm74c923_device : public mm74c922_device { public: // construction/destruction mm74c923_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock); }; // device type definition DECLARE_DEVICE_TYPE(MM74C922, mm74c922_device) DECLARE_DEVICE_TYPE(MM74C923, mm74c923_device) #endif // MAME_MACHINE_MM74C922_H