Specifications

A-2 Sound Blaster I/O Address Maps
SB1.5 I/O Address Map
Sound Blaster version 1.5 or earlier uses I/O addresses 2x0h - 2xFh, where x is
number from 1 to 6.
Base Address I/O Addresses Used
210h 210h to 21Fh
220h 220h to 22Fh
230h 230h to 23Fh
240h 240h to 24Fh
250h 250h to 25Fh
260h 260h to 26Fh
Table A-1: SB1.5 I/O Ports
The following table lists the functions of the I/O ports:
I/O Address Description Access
Base + 0h C/MS Music Voice 1-6 Data Port Write Only
Base + 1h C/MS Music Voice 1-6 Register Port Write Only
Base + 2h C/MS Music Voice 7-12 Data Port Write Only
Base + 3h C/MS Music Voice 7-12 Register Port Write Only
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
Table A-2: SB1.5 I/O Port Functions
The C/MS Music Voice ports apply only when C/MS chips are present.
FM music can also be accessed through I/O addresses 388h and 389h.