
DMA Controller
9-6
9.3.3
DMA Transfer Count Registers
(D0TC, Offset C8h, D1TC, Offset D8h)
Each DMA channel maintains a 16-bit DMA Transfer Count register (DTC). This register
is decremented after each DMA cycle, regardless of the state of the TC bit in the DMA
control register. However, if the TC bit in the DMA control word is set or if unsynchronized
transfers are programmed, DMA activity terminates when the transfer count register
reaches 0.
Figure 9-3
DMA Transfer Count Registers
The value of D0TC and D1TC at reset is undefined.
Bits 15–0: DMA Transfer Count (TC15–TC0)—Contains the transfer count for a DMA
channel. Value is decremented by 1 after each transfer.
15
7
0
TC15–TC0
Summary of Contents for Am186 ES
Page 1: ...Am186 ES and Am188 ES User s Manual...
Page 4: ...iv...
Page 12: ...Table of Contents xii...
Page 22: ...Features and Performance 1 8...
Page 60: ...System Overview 3 28...
Page 84: ...Chip Select Unit 5 14...
Page 132: ...Timer Control Unit 8 8...
Page 166: ...Programmable I O Pins 11 6...
Page 184: ...Register Summary A 18...