Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-04-25 17:56:43 +03:00
Code Issues Actions Packages Projects Releases Wiki Activity

s14001a.c: Add note that the four dac test pins are really digital out pins [PlgDavid]

Browse Source
This commit is contained in:
Jonathan Gevaryahu 2013-03-14 16:27:02 +00:00
parent 02f7747023
commit 19c1afbe79
1 changed files with 8 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/emu/sound/s14001a.c
View File

@ -53,13 +53,13 @@ labeling.
_| |_
ROM CLOCK/CKR <- |_|4 37|_| <- ROM D6
_| |_
?DAC TEST? ?? |_|5 36|_| -> ROM A10
DIGITAL OUT 0 <- |_|5 36|_| -> ROM A10
_| |_
?DAC TEST? ?? |_|6 35|_| -> ROM A9
DIGITAL OUT 1 <- |_|6 35|_| -> ROM A9
_| |_
?DAC TEST? ?? |_|7 34|_| <- ROM D5
DIGITAL OUT 2 <- |_|7 34|_| <- ROM D5
_| |_
?DAC TEST? ?? |_|8 33|_| -> ROM A8
DIGITAL OUT 3 <- |_|8 33|_| -> ROM A8
_| |_
ROM /EN <- |_|9 32|_| <- ROM D4
_| S |_
@ -102,6 +102,10 @@ which is normally impossible. The later 'version 3' TSI speech board as featured
an advertisement in the John Cater book probably also has this feature, in addition
to external speech rom banking.
The Digital out pins supply a copy of the 4-bit waveform which also goes to the
internal DAC. They are only valid every other clock cycle. It is possible that
on 'invalid' cycles they act as a 4 bit input to drive the dac.
Because it requires -10V to operate, the chip manufacturing process must be PMOS.
/-----------\