Intel 386 - Manual (Page 79)

Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL
5-6
Figure 5-3. DMA Configuration Register (DMACFG)
DMA Configuration
DMACFG
(read/write) Expanded Addr:
ISA Addr:
Reset State: F830H
—
00H
7 0
D1MSK D1REQ2 D1REQ1 D1REQ0 D0MSK D0REQ2 D0REQ1 D0REQ0
Bit
Number
Bit
Mnemonic
Function
7 D1MSK DMA Acknowledge 1 Mask:
0 = DMA channel 1’s acknowledge (DMAACK1#) signal is not masked.
1 = Masks DMA channel 1’s acknowledge (DMAACK1#) signal. Useful
when channel 1’s request (DREQ1) input is connected to an internal
peripheral.
6–4 D1REQ2:0 DMA Channel 1 Request Connection:
Connects one of the eight possible hardware sources to channel 1’s
request input (DREQ1).
000 = DRQ1 pin (external peripheral)
001 = SIO channel 1’s receive buffer full signal (RBFDMA1)
010 = SIO channel 0’s transmit buffer empty signal (TXEDMA0)
011 = SSIO receive holding buffer full signal (SSRBF)
100 = TCU counter 2’s output signal (OUT2)
101 = SIO channel 0’s receive buffer full signal (RBFDMA0)
110 = SIO channel 1’s transmit buffer empty signal (TXEDMA1)
111 = SSIO transmit holding buffer empty signal (SSTBE)
3 D0MSK DMA Acknowledge 0 Mask:
0 = DMA channel 0’s acknowledge (DMAACK0#) signal is not masked.
1 = Masks DMA channel 0’s acknowledge (DMAACK0#) signal. Useful
when channel 0’s request (DREQ0) input is connected to an internal
peripheral.
2–0 D0REQ2:0 DMA Channel 0 Request Connection:
Connects one of the eight possible hardware sources to channel 0’s
request input (DREQ0).
000 = DRQ0 pin (external peripheral)
001 = SIO channel 0’s receive buffer full signal (RBFDMA0)
010 = SIO channel 1’s transmit buffer empty signal (TXEDMA1)
011 = SSIO transmit holding buffer empty signal (SSTBE)
100 = TCU counter 1’s output signal (OUT1)
101 = SIO channel 1’s receive buffer full signal (RBFDMA1)
110 = SIO channel 0’s transmit buffer empty signal (TXEDMA0)
111 = SSIO receive holding buffer full signal (SSRBF)