AD1816A

–39–

REV. A

Table X. AdLib ISA Bus Registers

Register Name

ISA Bus Address

Music0: Address (w), Status (r)

(AdLib Base) Relocatable in range 0x100 – 0x3F8

Music0: Data (w)

(AdLib Base+1)

Music1: Address (w)

(AdLib Base+2)

Music1: Data (w)

(AdLib Base+3)

MPU-401 Registers

The AD1816A contains a set of ISA Bus registers (ports) that correspond to those used by the ISA bus MIDI audio interface cards.

Table XI lists the ISA Bus MIDI registers. These registers support commands and data transfers described in MIDI 1.0 Detailed

Specification and Standard MIDI Files 1.0, © 1994, MIDI Manufacturers Association, PO Box 3173 La Habra, CA 90632-3173.

Table XI. MPU-401 ISA Bus Registers

Register Name

Address

MIDI Data (r/w)

(MIDI Base) Relocatable in range 0x100 to 0x3FE

MIDI Status (r), Command (w)

(MIDI Base+1)

0x(MIDI Base+1)

BIT

76543210

STATE

10000000

NAME

DRR

DSR

RESERVED

DSR (R)

Data Send Ready. When read, this bit indicates that you can (0) or cannot (1) write to the

MIDI Data register. (Full = 1, Empty = 0)

DRR (R)

Data Receive Ready. When read, this bit indicates that you can (0) or cannot (1) read from the

MIDI Data register. (Unreadable = 1, Readable = 0)

CMD [7:0] (W)

MIDI Command. Write MPU-401 commands to bits [7:0] of this register.

NOTES

The AD1816A supports only the MPU-401 0xFF (reset) and 0x3F (UART) commands. The controller powers setup for Smart

mode, but must be put in pass-through mode. To start MIDI operations, send a reset command (0xFF) and then send a UART

mode command (0x3F). The MPU-401 data register contains an acknowledge byte (0xFE) after each command transfer unless it is

in UART mode..

All commands return an ACK byte in “smart” mode.

Status commands (0xAx) return ACK and a data byte; all other commands return ACK.

All commands except reset (0xFF) are ignored in UART mode. No ACK bytes are returned.

“Smart” mode data transfers are not supported.

Game Port Registers

The AD1816A contains a Game Port ISA Bus Register that is compatible with the IBM joystick standard.

Table XII. Game Port ISA Bus Registers

Register Name

Address

Game Port I/O

(Game Port Base+0 to Game Port Base+7)

Relocatable in the range 0x100 to 0x3F8