diff options
| author | 2017-01-05 12:07:25 +0100 | |
|---|---|---|
| committer | 2017-01-05 12:12:33 +0100 | |
| commit | d83f35b3827b5a0f486111cdbfb6171e7031e3dc (patch) | |
| tree | 7ebb0b22140336fec4c0180642358ab7930aa4cd /src/devices/machine/phi.cpp | |
| parent | 5a82972fe58fee742fde68766da260d46f1a7218 (diff) | |
hp9845: cosmetic fixes to 9895-related source files
Diffstat (limited to 'src/devices/machine/phi.cpp')
| -rw-r--r-- | src/devices/machine/phi.cpp | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/src/devices/machine/phi.cpp b/src/devices/machine/phi.cpp index 2ac82a44326..34fa8d6117c 100644 --- a/src/devices/machine/phi.cpp +++ b/src/devices/machine/phi.cpp @@ -19,6 +19,12 @@ * C1,C2,C3,C4,C5 * HP non-standard IDENTIFY sequence + Fun fact: PHI has no clock input, its FSMs are driven only by + changes in input signals and by a few internal monostables + + Main reference for this ASIC: + HP 12009-90001, sep 82, HP12009A HP-IB Interface Reference Manual + *********************************************************************/ #include "emu.h" @@ -514,10 +520,12 @@ uint8_t phi_device::get_dio(void) void phi_device::set_dio(uint8_t data) { - LOG(("DIO=%02x\n" , data)); - m_dio = data; - if (!m_loopback) { - m_dio_write_func(~data); + if (data != m_dio) { + LOG(("DIO=%02x\n" , data)); + m_dio = data; + if (!m_loopback) { + m_dio_write_func(~data); + } } } |
