E-Mu Morpheus Betriebsanleitung PDF herunterladen (Seite 130)

Planet Phatt Operation Manual122

MIDI SPECIFICATIONS

• 14-bit Signed 2's Complement Numbers

If the data value is negative, you must first take the 2's complement of

the number: In the case of a 14-bit number this is equivalent to

adding 16384 to the original negative value.

To fit the 7-bit MIDI protocol, numbers must be “nibble-ized”.

To get the 14-bit nibble-ized value (of a positive value or a 2's

complemented negative value):

msb = value DIV 128 (divide and ignore the remainder)

lsb = value MOD 128 (divide and use only the remainder)

To go the other way (convert 14 bit signed 2's complement to a signed

real number)

raw Value = (msb*128) + lsb (gives you the unsigned raw value)

if raw Value ≥ 8192 (8192 = 2^13)

then signed Value = raw value - 16384 (16384 = 2^14)

Example: To find the “nibble-ized” Hex value of -127:

1) -127 + 16384 = 16252

2) 16252 ÷ 128 = 126 r-124

3) 126 in Hex = 7E = msb

4) 124 in Hex = 7C = lsb

5) Parameter value would be transmitted as 7C 7E

Example: To find the “nibble-ized” Hex value of parameter number

257:

1) 257 ÷ 128 = 2 r-1

2) 2 in Hex = 02 = msb

3) 1 in Hex = 01 = lsb

4) Parameter number would be transmitted as 01 02

00000000 00000000

{

data bits data bits

Status

Bit

Status

Bit

Status Bit MUST be “0”

in MIDI data bytes.

1 2 ... 125 126 127 128 129 130 131 132 133 134 135 ... 139 140

Keine Kommentare

E-Mu Morpheus Betriebsanleitung Seite 130