Programming Considerations
http://www.motorola.com/computer/literature
2-13
2
DMA Channels
The PIB supports seven DMA channels. Channels 0 through 3 support
8-bit DMA devices. Channels 5 through 7 are dedicated to 16-bit DMA
devices. The channels are allocated as follows:
Sources of Reset
The MVME2603/2604 SBC has eight potential sources of reset:
1. Power-on reset
2.
RESET
switch (resets the VMEbus when the MVME2603/2604 is
system controller)
3. Watchdog timer Reset function controlled by the SGS-Thomson
MK48T559 timekeeper device (resets the VMEbus when the
MVME2603/2604 is system controller)
Table 2-3. IBC DMA Channel Assignments
IBC
Priority
IBC
Label
Controller
DMA Assignment
1
Channel 0
DMA1
Serial Port 3 Receiver (Z85230 Port A Rx)
2
Channel 1
Serial Port 3 Transmitter (Z85230 Port A
Tx)
3
Channel 2
Floppy Drive Controller
4
Channel 3
Parallel Port
5
Channel 4
DMA2
Not available — Cascaded from DMA1
6
Channel 5
Serial Port 4 Receiver (Z85230 Port B Rx)
7
Channel 6
Serial Port 4 Transmitter (Z85230 Port B
Tx)
8
Channel 7
Not Used
