Memory Maps
http://www.motorola.com/computer/literature
2-7
2
DMA Channels
The PBC 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 MCP750HA SBC has seven potential sources of reset:
1. Power-on/Undervoltage Reset.
2. Front Panel
RESET
switch (will generate a hard reset when
depressed).
3. Reset and Abort Header J21 Pins 2-3.
4. Watchdog timer Reset function controlled by the SGS-Thomson
MK48T559 Watchdog Timer or the Raven Watchdog Timers.
5. Port 92 Register via the PBC
6. CompactPCI Bus via the 21154 Bridge Control Register.
7. Optional external reset from J5 pin A22.
Table 2-2. PBC DMA Channel Assignments
PBC
Priority
PBC
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
Summary of Contents for MCP750HA Series
Page 161: ......