void vt100_state::nvr_latch_w(u8 data) { // data inverted due to negative logic m_nvr->c3_w(!BIT(data, 3)); m_nvr->c2_w(!BIT(data, 2)); m_nvr->c1_w(!BIT(data, 1)); // C2 is used to disable pullup on data line m_nvr->data_w(BIT(data, 2) ? 0 : !BIT(data, 0)); // SPDS present on pins 11, 19 and 23 of EIA connector m_rs232->write_spds(BIT(data, 5)); }