Isa Dma Channels; Table 1-23. Pib Dma Channel Assignments - Motorola MVME2600 Series Reference Manual

ISA DMA Channels

There are seven ISA DMA channels in the PIB. Channels 0 through 3
support only 8-bit DMA devices while Channels 5 through 7 support only
16-bit DMA devices. These DMA channels are assigned as follows:

Table 1-23. PIB DMA Channel Assignments

PIB
PIB Label
Priority
Highest Channel 0
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
Lowest Channel 7
Note
Controller
DMA1 Serial Port 3 Receiver (Z85230 Port A Rx)
Serial Port 3 Transmitter (Z85230 Port A Tx)
Floppy Drive Controller
Parallel Port
DMA2 Not available - Cascaded from DMA1
Serial Port 4 Receiver (Z85230 Port B Rx)
Serial Port 4 Transmitter (Z85230 Port B Tx)
Not Used
Because the Z85230 is an 8-bit device and Channels 5 and 6
are 16-bit DMA Channels, only every other byte (the even
bytes) from memory is valid.
ISA Local Resource Bus
DMA Assignment
1
1-49