19.009 Does anyone know where I can get some details on MockingBoard hardware and programming?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
19.009 Does anyone know where I can get some details on MockingBoard hardware and programming?
MockingBoard Mini-Manual 11/97 version
By: Rubywand
Part 1: Kinds of MockingBoards
The original MockingBoards come in four basic 'flavors':
Sound I-- produces music tones and a variety of sound
effects (3 voices to 1 Audio Output)
Speech I-- produces speech or limited sound effects
(1 voice output to 1 Audio Output)
Sound II-- 2 x Sound I on a single board (3+3 voices
to 2 Audio Outputs)
Sound/Speech I-- Sound I + Speech I on a single board
(3+1 voices to 2 Audio Outputs)
Note ...
Audio Output: This goes to a speaker or hi-fi amplifier
Voice: a musical note, sound effect, speech sound, etc.
Quite a few of the original MockingBoards were sold. Later MB's use model
names like "MockingBoard A", etc.. The main difference between the original
series and letter-named boards is wider availability of Speech.
Edhel Iaur and Mike Mahon supplied details on models A-D. Prices are from a
Sweet Micro Systems ad in the December, 1985 issue of _A+_ magazine:
MockingBoard A is a stereo music and sound synthesizer with six voices.
Suggested retail price is $99.00. This model has two sockets for adding speech
synthesis IC's so that a user could add speech to one or both Audio Outputs.
Except for the speech upgrade options, MB-A is very similar to the earlier
Sound II.
"MockingBoard B" is just the name of the Speech Upgrade; it is not a separate
MB board. The kit consists of one speech synthesizer chip. Earlier MB's used
the 16-pin SC-01 speech IC, while later board runs provided 24-pin sockets for
the newer (but somewhat flawed) SSI-263 speech synthesizer chip. Suggested kit
retail price is $89.00.
MockingBoard C is simply a MB-A that has been upgraded by plugging in one
speech chip. Suggested retail price is $179.00. (There was an 'undocumented'
upgrade, obtainable by plugging in the other speech chip, which allowed the
board to "sing harmony" with itself!)
MockingBoard D is a stereo music, sound and speech synthesizer for the Apple
IIc. It connects to a IIc through a serial port and is, of course, external
(unlike the Slot board models for other Apple II's). Its drivers are very
different from the slot I/O of the other MockingBoards. Suggested retail price
is $195.00.
Phasor is a MockingBoard-compatible sound card produced by Applied Engineering.
Looking at the software that comes with the Phasor may be helpful to MB users.
MockingBoards work on Apple II's with at least 48K RAM. MB can go into any
Slot (except for MB-D, which must plug into a IIc). Most programs expect it to
be in Slot 4; however, it is fairly common for a program which supports MB to
ask you to enter the Slot #.
Most for-MB products will work with Sound I, Sound II, Sound/Speech I, A,
and C. (Some work with D.) Products that use MB include Ultima III, IV, V Sky
Fox, Wiley Byte', Thunder Bombs, Lancaster, Under Fire, Music Construction Set,
GuitarMaster, and Music Star.
MB's 0.5 Watt Audio Output(s) can directly drive an 8 Ohm speaker. You can
also run the Output(s) to a hi-fi amplifier.
Except for speech-only models, MB uses the General Instruments AY-3-8910
Programmable Sound Generator IC. The PSG has 3 on-chip tone oscillators (via
channels A, B ,C) and a Noise Generator (NG). So, for example, the Sound II can
play up to 6 notes or effects at once. The NG on each PSG can be mixed with
any, all, or none of the three tones.
Many MB "Speech" version boards use the Votrax SC-01 Speech Synthesizer IC.
The SC-01 uses 64 phoneme sounds to produce speech. MB software lets you adjust
duration of each phoneme in 4 steps, create "rules" for custom sounds, and
speak sentences from text in BASIC programs. The SSI-263 speech synthesizer
appeared on later model MB's. (At present, more info on the SSI-263 is not
included here.)
All MB versions use the 6522 Versatile Interface IC to handle board I/O.
Except for the Sound I board, early models have circuit board points to which
you can add cables to utilize I/O ports not needed for Sound or Speech.
Part 2: Sound Programming
Each Programmable Sound Generator (PSG) has 3 output Channels: A, B, and C.
There are also 3 Tone oscillators, one committed to each Channel, and one Noise
Generator (NG) which can send its output to any Channel(s). Amplitude (output
Level or Volume) and Envelope Control ON/OFF is set for each Channel.
The PSG's Enable/Disable register has 8 bits. Three bits let you decide
whether or not to send a Tone oscillator''s output to its Channel. For example,
you can enable Tone outputs for the oscillators going through Channels A and B
while disabling Tone output for the oscillator connected to Channel C.
The Enable/Disable register also lets you decide whether or not to send the
Noise Generator's output through a Channel. Three bits let you decide which
Channel(s) the NG's output will go through. For example, you can enable NG
output through Channels A and C but not through B; or, disable NG output
through all three Channels, etc..
If, for example, Channel A's Tone oscillator output is enabled and NG
output is enabled for Channel A, then, a mixed Tone + NG signal will go through
Channel A. Setting Channel A's Amplitude controls the Level for the mixed
signal.
Often, a programmer will want to individually control the Levels of Tone
outputs (for music) and Noise outputs (for sound effects). This is accomplished
by using one PSG Channel only for Noise and two Channels only for Tones. Since
the MB Sound II has 2 PSG's, a typical game application using the board will
have 4 music tones and 2 effects sounds-- each individually controlled for
Level.
More specifically, the user can set Tone Frequency (12 bits, 4 coarse & 8
fine) and Amplitude (4 bits) for each channel individually. A fifth Amplitude
bit lets you decide if a channel's Level will be "fixed" (use the Level value)
or "variable" (i.e. follow the current Envelope pattern). You have 4 bits to
set Noise Generator Frequency.
Tone Freq = A2 Clock Freq/ [ (4096 x Coarse) + (16 x Fine) ]
Noise Freq = A2 Clock Freq/ (16 x NG value)
The Envelope of the combined outputs of enabled sources can be controlled
for Period (16 bits, 8 coarse & 8 fine)** and, roughly, for Shape (4 bits).
Env Freq = A2 Clock Freq/ [ (65536 x Coarse) + (256 x Fine) ]
The registers of the PSG are described briefly below:
Reg. Function and Bit(s) used
00 A Freq. fine (bits 0-7)
01 A Freq. coarse (bits 0-3)
02 B Freq. fine (bits 0-7)
03 B Freq. coarse (bits 0-3)
04 C Freq. fine (bits 0-7)
05 C Freq. coarse (bits 0-3)
06 NG Freq. (bits 0-4)
07 Enable/Disable note: Enable =0/ Disable =1
bit 5: NG sent to A
bit 4: NG sent to B
bit 3: NG sent to C
bit 2: A Tone
bit 1: B Tone
bit 0: C Tone
Ex: Writing $F0 to Reg 07 plays tones A, B, C plus noise on C
Ex: Writing $F8 to Reg 07 plays tones A, B, C and no noise
08 A Level (bits 0-3) and
Envelope Control (bit 4): 1 = Use Env; 0 = Use Level value
09 B Level (0-3) and
Envelope Control (bit 4): 1 = Use Env; 0 = Use Level value
0A C Level (0-3) and
Envelope Control (bit 4): 1 = Use Env; 0 = Use Level value
0B Envelope Period Fine (bits 0-7)
0C Envelope Period Coarse (bits 0-7)
0D Envelope Shape (four bits):
Continue (bit 3) 0= do 1 cycle and set Level to zero
Attack (bit 2) 1= count up 0= count down
Alternate (bit 1) 1= reverse count direction each cycle
Hold (bit 0) 1= do 1 cycle and hold count
To program the MB you write to the board's 6522 I/O chip(s). All address
references here are for a MB Sound II (2 Audio Outputs) in Slot 4.
$C400 ORB1 function to perform, Output 1
$C480 ORB2 function to perform, Output 2
$C401 ORA1 data, Output 1
$C481 ORA2 data, Output 2
$C402 DDRB1 data direction, Output 1
$C482 DDRB2 data direction, Output 2
$C403 DDRA1 data direction, Output 1
$C483 DDRA2 data direction, Output 2
Before sending music, etc. data to the MB you must Initialize the board's I/O.
To Initialize the 6522's: Store $FF at $C402 and the other three DDRxx
addresses. This needs to be done by your program just once.
Your program gets access to a PSG via the 6522 by using a few basic Function
codes which set the PSG's I/O control lines:
Set Inactive = $04
Set PSG Reg# = $07
Write Data = $06
Reset = $00
To Write to a PSG register: Tell the PSG which Register you wish to access
(i.e. Set the "current register" #) and Write the data. This is easiest to do
with subroutines to handle the basic Functions.
Example Subroutines (for Output Channel 1):
Set Reg # 1000: A9 07 8D 00 C4 A9 04 8D 00 C4 60
Write Data 100B: A9 06 8D 00 C4 A9 04 8D 00 C4 60
Notice that each Function sub ends by setting the PSG control lines to
Inactive.
Similarly, to do a Reset (set all PSG regs to zero) ...
Reset 1016: A9 00 8D 00 C4 A9 04 8D 00 C4 60
To put the value $55 in PSG Register 02 (Channel B Freq. fine) ....
1080: A9 02 put Reg in A (6502 accumulator register)
1082: 8D 01 C4 store A at the Data address ORA1
1085: 20 00 10 JSR to Set Reg (sets "current register" to Reg 2)
1088: A9 55 put the value $55 in A
108A: 8D 01 C4 store A at the Data address ORA1
108D: 20 0B 10 JSR to Write Data ($55 goes into PSG Register 2)
1090: 60 Exit from subroutine
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