Rev.A Hardware Specifications 5-5
Developer's Guide SR-600
Confidential
DMA
The 8237A-, which is equivalent to two DMA controllers and supports seven DMA channels, is
mounted in the SR-600. Channels 0, 1, 2, and 3 provide 8-bit data transfers; channels 5, 6, and 7
provide 16-bit data transfers. The SR-600 uses channel 2 for the floppy disk drive con tro ll er, and
releases other channels to the ISA bus.
The DMA channel assignments are shown below.
* When LPT1 is in ECP mode, use one of the channels.
Table 5-2 DMA channel assignments
Controller Channel Application
DMA1 8 bits 0 (Spare)
1 (Spare *)
2Floppy disk controller
3 (Spare *)
DMA2 16 bits 4 Controller 1 cascade connection
5 (Spare)
6 (Spare)
7 (Spare)