diff options
Diffstat (limited to 'src/devices/sound/astrocde.cpp')
-rw-r--r-- | src/devices/sound/astrocde.cpp | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/src/devices/sound/astrocde.cpp b/src/devices/sound/astrocde.cpp index 33ae926f34c..8a99a9f3988 100644 --- a/src/devices/sound/astrocde.cpp +++ b/src/devices/sound/astrocde.cpp @@ -42,15 +42,14 @@ ************************************************************ The device has active high(!) SO strobes triggered by - read accesses, which transfer data from the the 8 SI - lines to the bus. Logically SO0-7 and SI0-7 ought to - be hooked up to the same input matrix, but this only - appears to be the case with the Astrocade home systems. - The arcade games instead channel the SI inputs through - a quartet of MC14539B (pin-compatible with 74153) CMOS - multiplexers and connect the SO strobes to unrelated - outputs which generally use the upper 8 address bits - as data. + read accesses, which transfer data from the 8 SI lines + to the bus. Logically SO0-7 and SI0-7 ought to be hooked + up to the same input matrix, but this only appears to be + the case with the Astrocade home systems. The arcade + games instead channel the SI inputs through a quartet of + MC14539B (pin-compatible with 74153) CMOS multiplexers + and connect the SO strobes to unrelated outputs which + generally use the upper 8 address bits as data. ***********************************************************/ |