/***************************************************************************** 74153 Dual 4-line to 1-line data selectors/multiplexers Pin layout and functions to access pins: enable_w(0) [1] /1G VCC [16] b_w [2] B /2G [15] enable_w(1) input_line_w(0,3) [3] 1C3 A [14] a_w input_line_w(0,2) [4] 1C2 2C3 [13] input_line_w(1,3) input_line_w(0,1) [5] 1C1 2C2 [12] input_line_w(1,2) input_line_w(0,0) [6] 1C0 2C1 [11] input_line_w(1,1) output_r(0) [7] 1Y 2C0 [10] input_line_w(1,0) [8] GND 2Y [9] output_r(1) Truth table (all logic levels indicate the actual voltage on the line): INPUTS | OUTPUT | G | B A | C0 C1 C2 C3 | Y --+------+-------------+--- 1 H | X X | X X X X | L 2 L | L L | X X X X | C0 3 L | L H | X X X X | C1 4 L | H L | X X X X | C2 5 L | H H | X X X X | C3 --+------+-------------+--- L = lo (0) H = hi (1) X = any state *****************************************************************************/ #include "emu.h" #include "machine/74153.h" typedef struct _ttl74153_state ttl74153_state; struct _ttl74153_state { /* callback */ void (*output_cb)(device_t *device); /* inputs */ int a; /* pin 14 */ int b; /* pin 2 */ int input_lines[2][4]; /* pins 3-6,10-13 */ int enable[2]; /* pins 1,15 */ /* output */ int output[2]; /* pins 7,9 */ /* internals */ int last_output[2]; }; INLINE ttl74153_state *get_safe_token(device_t *device) { assert(device != NULL); assert(device->type() == TTL74153); return (ttl74153_state *)downcast(device)->token(); } void ttl74153_update(device_t *device) { ttl74153_state *state = get_safe_token(device); int sel; int section; sel = (state->b << 1) | state->a; /* process both sections */ for (section = 0; section < 2; section++) { if (state->enable[section]) state->output[section] = 0; // row 1 in truth table else state->output[section] = state->input_lines[section][sel]; } /* call callback if either of the outputs changed */ if ( state->output_cb && ((state->output[0] != state->last_output[0]) || (state->output[1] != state->last_output[1]))) { state->last_output[0] = state->output[0]; state->last_output[1] = state->output[1]; state->output_cb(device); } } void ttl74153_a_w(device_t *device, int data) { ttl74153_state *state = get_safe_token(device); state->a = data ? 1 : 0; } void ttl74153_b_w(device_t *device, int data) { ttl74153_state *state = get_safe_token(device); state->b = data ? 1 : 0; } void ttl74153_input_line_w(device_t *device, int section, int input_line, int data) { ttl74153_state *state = get_safe_token(device); state->input_lines[section][input_line] = data ? 1 : 0; } void ttl74153_enable_w(device_t *device, int section, int data) { ttl74153_state *state = get_safe_token(device); state->enable[section] = data ? 1 : 0; } int ttl74153_output_r(device_t *device, int section) { ttl74153_state *state = get_safe_token(device); return state->output[section]; } static DEVICE_START( ttl74153 ) { ttl74153_config *config = (ttl74153_config *)downcast(device->baseconfig()).inline_config(); ttl74153_state *state = get_safe_token(device); state->output_cb = config->output_cb; device->save_item(NAME(state->enable)); device->save_item(NAME(state->last_output)); device->save_item(NAME(state->input_lines[0][0])); device->save_item(NAME(state->input_lines[0][1])); device->save_item(NAME(state->input_lines[0][2])); device->save_item(NAME(state->input_lines[0][3])); device->save_item(NAME(state->input_lines[1][0])); device->save_item(NAME(state->input_lines[1][1])); device->save_item(NAME(state->input_lines[1][2])); device->save_item(NAME(state->input_lines[1][3])); device->save_item(NAME(state->a)); device->save_item(NAME(state->b)); } static DEVICE_RESET( ttl74153 ) { ttl74153_state *state = get_safe_token(device); state->a = 1; state->b = 1; state->enable[0] = 1; state->enable[1] = 1; state->input_lines[0][0] = 1; state->input_lines[0][1] = 1; state->input_lines[0][2] = 1; state->input_lines[0][3] = 1; state->input_lines[1][0] = 1; state->input_lines[1][1] = 1; state->input_lines[1][2] = 1; state->input_lines[1][3] = 1; state->last_output[0] = -1; state->last_output[1] = -1; } static const char DEVTEMPLATE_SOURCE[] = __FILE__; #define DEVTEMPLATE_ID(p,s) p##ttl74153##s #define DEVTEMPLATE_FEATURES DT_HAS_START | DT_HAS_RESET | DT_HAS_INLINE_CONFIG #define DEVTEMPLATE_NAME "74153" #define DEVTEMPLATE_FAMILY "TTL" #include "devtempl.h" DEFINE_LEGACY_DEVICE(TTL74153, ttl74153);