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r24592 Wednesday 31st July, 2013 at 06:22:14 UTC by Aaron Giles
Make sure shift register is clear at the start of a read to simulate the
dummy 0 bit. Fix polarity of CS/CLK lines in mitchell.c.
[src/emu/machine]eepromser.c
[src/mame/drivers]mitchell.c

trunk/src/emu/machine/eepromser.c
r24591r24592
527527   switch (m_command)
528528   {
529529      // advance to the READING_DATA state; data is fetched after first CLK
530      // reset the shift register to 0 to simulate the dummy 0 bit that happens prior
531      // to the first clock
530532      case COMMAND_READ:
533         m_shift_register = 0;
531534         set_state(STATE_READING_DATA);
532535         break;
533536         
trunk/src/mame/drivers/mitchell.c
r24591r24592
9696
9797WRITE8_MEMBER(mitchell_state::eeprom_cs_w)
9898{
99   m_eeprom->cs_write(data ? CLEAR_LINE : ASSERT_LINE);
99   m_eeprom->cs_write(data ? ASSERT_LINE : CLEAR_LINE);
100100}
101101
102102WRITE8_MEMBER(mitchell_state::eeprom_clock_w)
103103{
104   m_eeprom->clk_write(data ? CLEAR_LINE : ASSERT_LINE);
104   m_eeprom->clk_write(data ? ASSERT_LINE : CLEAR_LINE);
105105}
106106
107107WRITE8_MEMBER(mitchell_state::eeprom_serial_w)
108108{
109   m_eeprom->di_write(data);
109   m_eeprom->di_write(data & 1);
110110}
111111
112112

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