static void write_register(uint8_t data, bool register_sel) {
busy_wait();
if(register_sel) set_rs();
else clear_rs();
clear_rw();
config_bus_output();
output_nibble(data);
output_nibble(data << 4);
config_bus_input();
}
/*
* Writes a byte to the pin register in 2 4 bit nibbles
* Uses append/remove functions such that it maintains current pin state
*/
void write_4_bits(int bits, int char_mode) {
usleep(1000);
reset_all();
set_rs(char_mode);
write_pins_append(bits>>4);
pulse_enable();
write_pins_remove(0xf);
write_pins_append(bits&0xf);
pulse_enable();
usleep(500);
reset_all();
}
uint8_t read_register(bool register_sel) {
uint8_t data = 0;
uint8_t upper4 = 0;
uint8_t lower4 = 0;
if(register_sel) set_rs();
else clear_rs();
set_rw();
config_bus_input();
upper4 = pulse_e();
lower4 = pulse_e();
data |= upper4;
data |= (lower4 >> 4);
return data;
}