DMA_TCDn_ATTR field descriptions (continued)Field DescriptionSee the SSIZE definition22.3.25 TCD Minor Byte Count (Minor Loop Mapping Disabled)(DMA_TCDn_NBYTES_MLNO)This register, or one of the next two registers (TCD_NBYTES_MLOFFNO,TCD_NBYTES_MLOFFYES), defines the number of bytes to transfer per request.Which register to use depends on whether minor loop mapping is disabled, enabled butnot used for this channel, or enabled and used.TCD word 2 is defined as follows if:• Minor loop mapping is disabled (CR[EMLM] = 0)If minor loop mapping is enabled, see the TCD_NBYTES_MLOFFNO andTCD_NBYTES_MLOFFYES register descriptions for the definition of TCD word 2.Address: 4000_8000h base + 1008h offset + (32d × i), where i=0d to 15dBit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0R NBYTESWReset x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x** Notes:x = Undefined at reset.•DMA_TCDn_NBYTES_MLNO field descriptionsField DescriptionNBYTES Minor Byte Transfer CountNumber of bytes to be transferred in each service request of the channel. As a channel activates, theappropriate TCD contents load into the eDMA engine, and the appropriate reads and writes perform untilthe minor byte transfer count has transferred. This is an indivisible operation and cannot be halted. It can,however, be stalled by using the bandwidth control field, or via preemption. After the minor count isexhausted, the SADDR and DADDR values are written back into the TCD memory, the major iterationcount is decremented and restored to the TCD memory. If the major iteration count is completed,additional processing is performed.NOTE: An NBYTES value of 0x0000_0000 is interpreted as a 4 GB transfer.Chapter 22 Enhanced Direct Memory Access (eDMA)K22F Sub-Family Reference Manual, Rev. 4, 08/2016NXP Semiconductors 471
