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mcs51: fix P3.1 output logic

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* mode 0 is still incorrect
This commit is contained in:
Patrick Mackinlay 2025-01-10 16:11:53 +07:00
parent fe1b9eac21
commit c81d74ebd9
2 changed files with 19 additions and 7 deletions
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25
src/devices/cpu/mcs51/mcs51.cpp
View File

@ -1042,14 +1042,18 @@ void mcs51_cpu_device::do_sub_flags(uint8_t a, uint8_t data, uint8_t c)
void mcs51_cpu_device::transmit(int state)
{
if (BIT(SFR_A(ADDR_P3), 1) != state)
if (m_uart.txd != state)
{
if (state)
SFR_A(ADDR_P3) |= 1U << 1;
else
SFR_A(ADDR_P3) &= ~(1U << 1);
m_uart.txd = state;
m_port_out_cb[3](SFR_A(ADDR_P3));
// P3.1 = SFR(P3) & TxD
if (BIT(SFR_A(ADDR_P3), 1))
{
if (state)
m_port_out_cb[3](SFR_A(ADDR_P3));
else
m_port_out_cb[3](SFR_A(ADDR_P3) & ~0x02);
}
}
}
@ -2230,7 +2234,13 @@ void mcs51_cpu_device::sfr_write(size_t offset, uint8_t data)
case ADDR_P0: m_port_out_cb[0](data); break;
case ADDR_P1: m_port_out_cb[1](data); break;
case ADDR_P2: m_port_out_cb[2](data); break;
case ADDR_P3: m_port_out_cb[3](data); break;
case ADDR_P3:
// P3.1 = SFR(P3) & TxD
if (!m_uart.txd)
m_port_out_cb[3](data & ~0x02);
else
m_port_out_cb[3](data);
break;
case ADDR_SBUF:
LOGMASKED(LOG_TX, "tx byte 0x%02x\n", data);
m_uart.data_out = data;
@ -2486,6 +2496,7 @@ void mcs51_cpu_device::device_reset()
m_uart.rx_clk = 0;
m_uart.tx_clk = 0;
m_uart.txbit = SIO_IDLE;
m_uart.txd = 0;
m_uart.rxbit = SIO_IDLE;
m_uart.rxb8 = 0;
m_uart.smod_div = 0;

1
src/devices/cpu/mcs51/mcs51.h
View File

@ -130,6 +130,7 @@ protected:
uint8_t data_out; //Data to send out
uint8_t data_in;
uint8_t txbit;
uint8_t txd;
uint8_t rxbit;
uint8_t rxb8;