// license:BSD-3-Clause // copyright-holders:Aaron Giles /***************************************************************************** 7474 positive-edge-triggered D-type flip-flop with preset, clear and complementary outputs. There are 2 flip-flops per chips Pin layout and functions to access pins: clear_w [1] /1CLR VCC [14] d_w [2] 1D /2CLR [13] clear_w clock_w [3] 1CLK 2D [12] d_w preset_w [4] /1PR 2CLK [11] clock_w output_r [5] 1Q /2PR [10] preset_w output_comp_r [6] /1Q 2Q [9] output_r [7] GND /2Q [8] output_comp_r Truth table (all logic levels indicate the actual voltage on the line): INPUTS | OUTPUTS | PR CLR CLK D | Q /Q --------------+------- L H X X | H L H L X X | L H L L X X | H H (Note 1) H H _- X | D /D H H L X | Q0 /Q01 --------------+------- L = lo (0) H = hi (1) X = any state _- = raising edge Q0 = previous state Note 1: Non-stable configuration *****************************************************************************/ #ifndef MAME_MACHINE_TTL7474_H #define MAME_MACHINE_TTL7474_H #pragma once //************************************************************************** // TYPE DEFINITIONS //************************************************************************** // ======================> ttl7474_device class ttl7474_device : public device_t { public: // construction/destruction ttl7474_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock); // static configuration helpers auto output_cb() { return m_output_func.bind(); } auto comp_output_cb() { return m_comp_output_func.bind(); } // public interfaces void clear_w(int state); void preset_w(int state); void clock_w(int state); void d_w(int state); int output_r(); int output_comp_r(); // NOT strictly the same as !output_r() protected: // device_t implementation virtual void device_start() override; virtual void device_reset() override; private: // callbacks devcb_write_line m_output_func; devcb_write_line m_comp_output_func; // inputs uint8_t m_clear; // pin 1/13 uint8_t m_preset; // pin 4/10 uint8_t m_clk; // pin 3/11 uint8_t m_d; // pin 2/12 // outputs uint8_t m_output; // pin 5/9 uint8_t m_output_comp; // pin 6/8 // internal uint8_t m_last_clock; uint8_t m_last_output; uint8_t m_last_output_comp; void update(); void init(); }; // device type definition DECLARE_DEVICE_TYPE(TTL7474, ttl7474_device) #endif // MAME_MACHINE_TTL7474_H