Jupiter-II Expansion

An Expansion board for the Jupiter-II computer

Expands Jupiter-II with

• Video color: 16 colors, RGB output
• Programmable Sound Generator
• 128K RAM: paged
• 16K ROM: FORTH vocabulary extension
• Serial Interface

FORTH code examples

Colors

CYAN BORDER ( Change screen border color )
WHITE PAPER ( Set char background color )
BLUE DARK INK ( Set char foreground color ) 

: COLORBAR
  CLS 10 8 AT 16 0
  DO
   I INK 144 EMIT
  LOOP 
  BLACK INK
  ;
COLORBAR ( Show a colorfull bar )

Memory/Screen/Font Paging

0 FONT  ( select alternative character set )
1 FONT  ( select original character set )

0 SCREEN ( select screen page 0 )
1 SCREEN ( select screen page 1 )

0 MPAGE ( select memory page 0 )
3 MPAGE ( select memory page 3 )

Sounds

: PING
  200 0 PSG!
  254 7 PSG!
  16 8 PSG!
  20 12 PSG!
  1 13 PSG!
;

: SHOT
  8 6 PSG!
  247 7 PSG!
  16 8 PSG!
  20 12 PSG!
  1  13 PSG!
;

Serial Comm Port

8 data bits, 1 stop bit, no parity.

CREATE BUFFER 256 ALLOT ( Create and Allocate a memory space to work )
: CLRBUF BUFFER 256 32 FILL ; ( Clear Buffer )
: PRTBUF CR 256 0 DO BUFFER I + EMIT LOOP CR ; ( Print Buffer )

9600 BAUD     ( set communication baud rate )
CLRBUF        ( Clear Buffer )
BUFFER 256 RX ( Receive 256 bytes from serial line )
PRTBUF        ( View received data )
BUFFER 256 TX ( Transmit 256 bytes over serial line )

Note: use Space key to abort communication if needed

Extra FORTH vocabulary

The extended vocabulary is copied from XROM to a unused 1K RAM area at $3000-$33FF of Jupiter-II during initialization. That allows safe memory paging while keeping the extra Words accessible.

Standard FORTH words

COUNT ( addr -- addr+1 c )  Extract String length
+! ( n addr -- )  Add 'n' to 'addr' variable
? ( addr -- )  Print variable value
CMOVE ( addr1 addr2 n -- )  Copy 'n' bytes from 'addr1' to 'addr2'
FILL  ( addr n c -- )  Fill 'n' bytes with 'c' starting from 'addr'
DEPTH ( -- n )  Data Stack Depth
HEX   ( -- )  Set numeric base to Hexadecimal

Programmable Sound Generator

PSG! ( c reg -- ) Write 'c' to PSG register 'reg'
PSG@ ( reg -- c ) Read PSG register 'reg' contents

Colors

BORDER ( c -- ) Set screen BORDER to color 'c' , 0 to 15
INK    ( c -- ) Set character INK to color 'c' , 0 to 15
PAPER  ( c -- ) Set character PAPER to color 'c' , 0 to 15
BLACK  ( -- c ) Stack color code for Black
GREY   ( -- c ) Stack color code for Grey
BLUE   ( -- c ) Stack color code for Blue
GREEN  ( -- c ) Stack color code for Green
CYAN   ( -- c ) Stack color code for Cyan
RED    ( -- c ) Stack color code for Red
PURPLE ( -- c ) Stack color code for Purple
YELLOW ( -- c ) Stack color code for Yellow
WHITE  ( -- c ) Stack color code for White
DARK   ( c1 -- c2 ) Change color code on stack to a darker tone

Serial Communication

8 data bits, 1 stop bit, no parity.

BAUD ( n --  )  Set UART to Baud rate 'n'
TX ( addr n --  )  Transmit 'n' bytes starting from 'addr' to serial line
RX ( addr n --  )  Receive 'n' bytes from serial line to memory 'addr'

Avoid transfering to/from video RAM using video circuit priority addressing. That prevents transfer speeds above 1200 bauds.

• Video RAM from $2400 to $27FF. Use mirror addressing $2000 to $23FF instead (CPU priority).
• Character Genrator RAM from $2C00 to $2FFF. Use mirror addressing $2800 to $2BFF instead (CPU priority).

Note: Character Generator RAM is write only

Memory Paging

MPAGE  ( c -- ) Select memory page 'c' , 0 to 3
SCREEN ( c -- ) Select Screen page 'c' , 0 or 1
FONT   ( c -- ) Select character set 'c' , 0 or 1

Note: System resets to page 3

Programmable Sound Generator Registers

   bits: 76543210 76543210
  R1 R0: ----tttt tttttttt : Tone generator A period (12-bits) 0-4095
  R3 R2: ----tttt tttttttt : Tone generator B period (12-bits) 0-4095
  R5 R4: ----tttt tttttttt : Tone generator C period (12-bits) 0-4095
     R6:          ---ttttt : Noise generator period  (5-bits)  0-31
     R7:          ppcbaCBA : I/O port and sound channel enablers
     R8:          ---Mvvvv : Channel A Volume (v) and Envelope Mode (M)
     R9:          ---Mvvvv : Channel B Volume (v) and Envelope Mode (M)
    R10:          ---Mvvvv : Channel C Volume (v) and Envelope Mode (M)
R12 R11: tttttttt tttttttt : Envelope period (16-bits) 0-65535
    R13:          ----calh : Envelope Shape: Continue (c), Attack (a), Alternate(l), Hold (h)
    R14:          dddddddd : I/O Port-A data
    R15:          dddddddd : I/O Port-B data

R0..R6: Tone and Noise Period (Frequency) settings

t = 203125 / f , where f is the desirable frequency in Hz
Tone Range: 49.6 Hz to 203.1 kHz (0..4095)
Noise Range: 6.55 kHz to 293.1 kHz (0..31)

R7: Tone and Noise Mixer and I/O Ports direction

• bit0: when 0 enables tone A on channel A, 1 disables it
• bit1: when 0 enables tone B on channel B, 1 disables it
• bit2: when 0 enables tone C on channel C, 1 disables it
• bit3: when 0 enables Noise on channel A, 1 disables it
• bit4: when 0 enables Noise on channel B, 1 disables it
• bit5: when 0 enables Noise on channel C, 1 disables it
• bit6: when 0 set digital Port-A as input, 1 set it as output
• bit7: when 0 set digital Port-B as input, 1 set it as output
  

R8..R10: Channel volume

• bit4 : when 0 volume is fixed, when 1 volume is Envelope controlled
• bit3-0: Fixed volume value (0-31)
  

R11, R12: Envelope period

t = s / 78.769e-6 , where s is the desirable period in seconds
Period range: 78.8 us to 5.16 seconds

R13: Envelope Shape combination

• bit3: Continue: when 1 follows Hold setting, when 0 resets down after one cycle
• bit2: Attack: when 1 attack ramps up, when 0 ramps down
• bit1: Alternate: when 1 envelope shape reverses on each cycle (up/down)
• bit0: Hold: when 1 limits to one cycle and sustain final value
  

R14, R15: Digital I/O Port data

• Port A (register 14) controls PAPER and INK colors
• Port B (register 15) controls BORDER color and paging