Creative SB0350 Hardware Programming Guide - Page 46
Creative SB0350 Manual
View all Creative SB0350 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 46 highlights
Digitized Sound I/O Programming 3-17 8-bit Mono High-Speed Single-cycle Transfer The following are the steps needed to perform 8-bit mono PCM high-speed singlecycle DMA mode transfer: 1. 2. 3. Set up the DSP interrupt service routine. Enable the interrupt used. Turn on the DAC speaker for digitized output. Otherwise, turn it off. to turn off the DAC speaker outp(wSBCBaseAddx+0xC, 0xD3) to turn on the DAC speaker outp(wSBCBaseAddx+0xC, 0xD1) Program the DMA controller for 8-bit single-cycle DMA mode transfer. Set the DSP transfer Time Constant. outp(wSBCBaseAddx+0xC, 0x40) outp(wSBCBaseAddx+0xC, bTimeConstant) 4. 5. 6. Set the DSP transfer block size. outp(wSBCBaseAddx+0xC, 0x48) outp(wSBCBaseAddx+0xC, wBlkSize.LowByte) outp(wSBCBaseAddx+0xC, wBlkSize.HighByte) wBlkSize is one byte less than the actual data transfer size. 7. Send an I/O command to start high-speed single-cycle DMA mode transfer. outp(wSBCBaseAddx+0xC, bCommand) bCommand is one of the following: bCommand 99h 91h Description 8-bit PCM high-speed input 8-bit PCM high-speed output When the DSP sends an interrupt, the following steps should be done in the interrupt service routine: 1. 2. Program the DMA controller for the next block. Set the DSP block size and program the DSP for the next block.