Creative SB0350 Hardware Programming Guide - Page 77

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5-2 MIDI Port I/O Programming SB-MIDI Mode SB-MIDI mode provides an interface for MIDI I/O in Normal mode as well as UART mode. UART mode requires a DSP with a minimum version of 2.00. Under Normal mode, all MIDI out data must be preceded by a MIDI output command, but under UART mode, a write to the DSP is taken as MIDI data. In-bound MIDI data can be detected using a polling or interrupt mode. It is suggested that the interrupt mode be used for reading the in-bound MIDI data as the DSP will generate an interrupt to signal the application whenever there is any inbound MIDI data. This eliminates the time needed to keep polling for the in-bound MIDI data under polling mode. MIDI time stamp mode which conforms to Microsoft Multimedia Extension Level 1 Specifications, is also available on DSP version 2.00 and above. Under MIDI time stamp mode, in-bound MIDI data is tagged with a time stamp which can be used by a MIDI sequencer to replay the data at the proper tempo. I/O Addresses SB-MIDI mode shares the same I/O ports and 8-bit DMA mode interrupt status bit associated with digitized sound. This means that you can access the MIDI port by writing to and reading from the DSP. Refer to the chapter on "Introduction to DSP Programming" for information on accessing the DSP.

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5-2
MIDI Port I/O Programming
SB-MIDI Mode
SB-MIDI mode provides an interface for MIDI I/O in Normal mode as well as UART
mode.
UART mode requires a DSP with a minimum version of 2.00.
Under Normal
mode, all MIDI out data must be preceded by a MIDI output command, but under
UART mode, a write to the DSP is taken as MIDI data.
In-bound MIDI data can be detected using a polling or interrupt mode.
It is
suggested that the interrupt mode be used for reading the in-bound MIDI data as the
DSP will generate an interrupt to signal the application whenever there is any in-
bound MIDI data.
This eliminates the time needed to keep polling for the in-bound
MIDI data under polling mode.
MIDI time stamp mode which conforms to Microsoft Multimedia Extension Level 1
Specifications, is also available on DSP version 2.00 and above.
Under MIDI time
stamp mode, in-bound MIDI data is tagged with a time stamp which can be used by a
MIDI sequencer to replay the data at the proper tempo.
I/O Addresses
SB-MIDI mode shares the same I/O ports and 8-bit DMA mode interrupt status bit
associated with digitized sound.
This means that you can access the MIDI port by
writing to and reading from the DSP.
Refer to the chapter on "Introduction to DSP
Programming" for information on accessing the DSP.