A-6
Sound Blaster I/O Address Maps
SBPRO I/O Address Map
Sound Blaster Pro uses base I/O address 220h or 240h. These are jumper selectable.
Base Address
I/O Addresses Used
220h
220h to 233h
240h
240h to 253h
Table A-9: SBPRO I/O Ports
There are two versions of Sound Blaster Pro. The difference is in the FM chip used.
The earlier version uses a two-operator FM (OPL2) chip, while the later version uses
a four-operator FM (OPL3) chip.
The following table lists the functions of the I/O ports on the Sound Blaster Pro that
uses the OPL2 chip:
I/O Address
Description
Access
Base + 0h
Left FM Music Status Port
Read
Base + 0h
Left FM Music Register Address Port
Write
Base + 1h
Left FM Music Data Port
Write Only
Base + 2h
Right FM Music Status Port
Read
Base + 2h
Right FM Music Register Address Port
Write
Base + 3h
Right FM Music Data Port
Write Only
Base + 4h
Mixer chip Register Address Port
Write Only
Base + 5h
Mixer chip Data Port
Read/Write
Base + 6h
DSP Reset
Write Only
Base + 8h
FM Music Status Port
Read
Base + 8h
FM Music Register Port
Write
Base + 9h
FM Music Data Port
Write Only
Base + Ah
DSP Read Data Port
Read Only
Base + Ch
DSP Write Command/Data
Write
Base + Ch
DSP Write-Buffer Status (Bit 7)
Read
Base + Eh
DSP Read-Buffer Status (Bit 7)
Read Only
Base + 10h
CD-ROM Command or Data Register
Read/Write
Base + 11h
CD-ROM Status Register
Read Only
Base + 12h
CD-ROM Reset Register
Write Only
Base + 13h
CD-ROM Enable Register
Write Only
Table A-10: SBPRO with OPL2 I/O Port Functions
