This register is the disk-microprocessor data buffer. In read mode, data from the disk is placed into this register one byte at a time. As each byte is received into the register, the DSKBYT bit is set true. DSKBYT is cleared when the DSKBYTR register is read. DSKBYTR may be used to synchronize the processor to the disk rotation before issuing a read or write under DMA control. Table 8-7: DSKBYTR Register Bit Number Name Function ------ ---- -------- 15 DSKBYT When set, indicates that this register contains a valid byte of data (reset by reading this register). 14 DMAON Indicates when DMA is actually enabled. All the various DMA bits must be true. This means the DMAEN bit in DSKLEN , and the DSKEN & DMAEN bits in DMACON . 13 DISKWRITE The disk write bit (in DSKLEN ) is enabled. 12 WORDEQUAL Indicates the DSKSYNC register equals the disk input stream. This bit is true only while the input stream matches the sync register (as little as two microseconds). 11-8 Currently unused; don't depend on read value. 7-0 DATA Disk byte data.