Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07305 Sound Minor Always Apr 27, 2019, 13:06 5 days ago
Tester robcfg View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS MacOS X
Status [?] Confirmed Driver dragon.cpp
Version 0.209 Fixed in Version Build 64-bit
Summary MESS-specific 07305: dragon32, dragon64, dragon64h, dragon200, dragon200e: DAC sound not working
Description I did a small assembler program to play 3000hz sampled sound through the Dragon's DAC and found that it works as intended on a real Dragon and on XRoar, but on MAME it produces no sound at all.
Steps To Reproduce I've attached my program along a sampled sound, the original asm source code and a video of XRoar playing the sample for comparison.

Just start a Dragon machine with the vmailsnd.cas file and type:

CLOADM
CLOADM
EXEC 20000

The result should be as on the video, but actually MAME will remain silent.
Additional Information
Flags
Regression Version
Affected Sets / Systems dragon32, dragon64, dragon64h, dragon200, dragon200e
Attached Files
zip file icon Mametesters Dragon DAC Issue.zip (1,106,771 bytes) Apr 27, 2019, 13:06 Uploaded by robcfg
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Notes
5
User avatar
No.16595
Osso
Developer
17 days ago
As soon as the EXEC 20000 command is entered, MAME trips on an illegal opcode.
User avatar
No.16596
Robbbert
Developer
16 days ago
I got a period of silence followed by a screenful of garbage. Debug shows it in a loop for a while, followed by jumping into the weeds (zero-page ram).
User avatar
No.16630
robcfg
Tester
6 days ago
On the cas file, there is first the sample data and then the code.

So you should CLOADM once to load the data, CLOADM again to load the code and finally EXEC 20000 to run it.

Please tell me if there's anything I can help with.
User avatar
No.16631
Robbbert
Developer
6 days ago
edited on: 6 days ago
Corrected the instructions in "Steps to Reproduce".

Now it spends a couple of seconds writing to FF20 then finishing. I can confirm it makes no sound.
User avatar
No.16632
robcfg
Tester
5 days ago
The sound circuit is the same for the Dragon 32 and the Dragon 64, so you can use the restored Dragon 64 schematics from Richard Harding's site: http://www.dragondata.co.uk/tech/circuit-diag/D64/FS-White-Prints/Dragon-64K_CPU_PAL_CD41505-2_of_3-B.zip