pin = 0..15 value = LOW, HIGH
| 147 | // pin = 0..15 |
| 148 | // value = LOW, HIGH |
| 149 | bool MCP23S17::digitalWrite(uint8_t pin, uint8_t value) |
| 150 | { |
| 151 | if (pin > 15) |
| 152 | { |
| 153 | _error = MCP23S17_PIN_ERROR; |
| 154 | return false; |
| 155 | } |
| 156 | uint8_t IOR = MCP23S17_GPIO_A; |
| 157 | if (pin > 7) |
| 158 | { |
| 159 | IOR = MCP23S17_GPIO_B; |
| 160 | pin -= 8; |
| 161 | } |
| 162 | |
| 163 | uint8_t val = readReg(IOR); |
| 164 | uint8_t pre = val; |
| 165 | if (_error != MCP23S17_OK) |
| 166 | { |
| 167 | return false; |
| 168 | } |
| 169 | |
| 170 | uint8_t mask = 1 << pin; |
| 171 | if (value) |
| 172 | { |
| 173 | val |= mask; |
| 174 | } |
| 175 | else |
| 176 | { |
| 177 | val &= ~mask; |
| 178 | } |
| 179 | // only write when changed. |
| 180 | if (pre != val) |
| 181 | { |
| 182 | writeReg(IOR, val); |
| 183 | if (_error != MCP23S17_OK) |
| 184 | { |
| 185 | return false; |
| 186 | } |
| 187 | } |
| 188 | return true; |
| 189 | } |
| 190 | |
| 191 | |
| 192 | uint8_t MCP23S17::digitalRead(uint8_t pin) |