sn74x138.c (1895B)
1 /* Copyright 2022 2 * 3 * This program is free software: you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License as published by 5 * the Free Software Foundation, either version 2 of the License, or 6 * (at your option) any later version. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17 #include "sn74x138.h" 18 #include "gpio.h" 19 20 #define ADDRESS_PIN_COUNT 3 21 22 #ifndef SN74X138_ADDRESS_PINS 23 # error sn74x138: no address pins defined! 24 #endif 25 26 static const pin_t address_pins[ADDRESS_PIN_COUNT] = SN74X138_ADDRESS_PINS; 27 28 void sn74x138_init(void) { 29 for (int i = 0; i < ADDRESS_PIN_COUNT; i++) { 30 gpio_set_pin_output(address_pins[i]); 31 gpio_write_pin_low(address_pins[i]); 32 } 33 34 #if defined(SN74X138_E1_PIN) 35 gpio_set_pin_output(SN74X138_E1_PIN); 36 gpio_write_pin_high(SN74X138_E1_PIN); 37 #endif 38 39 #if defined(SN74X138_E2_PIN) 40 gpio_set_pin_output(SN74X138_E2_PIN); 41 gpio_write_pin_high(SN74X138_E2_PIN); 42 #endif 43 #if defined(SN74X138_E3_PIN) 44 gpio_set_pin_output(SN74X138_E3_PIN); 45 gpio_write_pin_low(SN74X138_E3_PIN); 46 #endif 47 } 48 49 void sn74x138_set_enabled(bool enabled) { 50 #if defined(SN74X138_E1_PIN) 51 gpio_write_pin(SN74X138_E1_PIN, !enabled); 52 #endif 53 #if defined(SN74X138_E2_PIN) 54 gpio_write_pin(SN74X138_E2_PIN, !enabled); 55 #endif 56 #if defined(SN74X138_E3_PIN) 57 gpio_write_pin(SN74X138_E3_PIN, enabled); 58 #endif 59 } 60 61 void sn74x138_set_addr(uint8_t address) { 62 for (int i = 0; i < ADDRESS_PIN_COUNT; i++) { 63 gpio_write_pin(address_pins[i], address & (1 << i)); 64 } 65 }