// 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 *****************************************************************************/ #pragma once #ifndef __TTL7474_H__ #define __TTL7474_H__ #include "emu.h" //************************************************************************** // INTERFACE CONFIGURATION MACROS //************************************************************************** #define MCFG_7474_OUTPUT_CB(_devcb) \ devcb = &ttl7474_device::set_output_cb(*device, DEVCB_##_devcb); #define MCFG_7474_COMP_OUTPUT_CB(_devcb) \ devcb = &ttl7474_device::set_comp_output_cb(*device, DEVCB_##_devcb); //************************************************************************** // TYPE DEFINITIONS //************************************************************************** // ======================> ttl7474_device class ttl7474_device : public device_t { public: // construction/destruction ttl7474_device(const machine_config &mconfig, std::string tag, device_t *owner, UINT32 clock); // static configuration helpers template static devcb_base &set_output_cb(device_t &device, _Object object) { return downcast(device).m_output_func.set_callback(object); } template static devcb_base &set_comp_output_cb(device_t &device, _Object object) { return downcast(device).m_comp_output_func.set_callback(object); } // public interfaces DECLARE_WRITE_LINE_MEMBER( clear_w ); DECLARE_WRITE_LINE_MEMBER( preset_w ); DECLARE_WRITE_LINE_MEMBER( clock_w ); DECLARE_WRITE_LINE_MEMBER( d_w ); DECLARE_READ_LINE_MEMBER( output_r ); DECLARE_READ_LINE_MEMBER( output_comp_r ); // NOT strictly the same as !output_r() protected: // device-level overrides virtual void device_start() override; virtual void device_reset() override; virtual void device_post_load() override { } virtual void device_clock_changed() override { } private: // callbacks devcb_write_line m_output_func; devcb_write_line m_comp_output_func; // inputs UINT8 m_clear; // pin 1/13 UINT8 m_preset; // pin 4/10 UINT8 m_clk; // pin 3/11 UINT8 m_d; // pin 2/12 // outputs UINT8 m_output; // pin 5/9 UINT8 m_output_comp; // pin 6/8 // internal UINT8 m_last_clock; UINT8 m_last_output; UINT8 m_last_output_comp; void update(); void init(); }; // device type definition extern const device_type TTL7474; #endif /* __TTL7474_H__ */