Dma Support; Table 2: Dma Support - Connect Tech ComSync/104 User Manual

DMA Support

To allow fast data reception and transmission, the ComSync/104 supports four DMA channels;
each one is assigned to one of the ESCC DMA Request pins. Each channel of the ESCC has 2
request pins which can be programmed as either a combined receive/transmit request or as
separate receive and transmit requests (see the ESCC Users Manual for much more detail).
The I/O of this card will support a DMA Enable for each Channel of the ESCC. The DMA
support is organized as follows:
PC/104 85230 DMA
DMA signals pin
DRQ0 / /DTR//REQA
DACK0#
DRQ1 / /W//REQA
DACK1#
DRQ2 / /DTR//REQB
DACK2#
DRQ3 / /W//REQB
DACK3#
Note: If a Floppy drive is installed in the system then DRQ2/DACK2#
are used and should not be used for the ComSync/104.

Table 2: DMA Support

85230
Chan 85230 Enable
nel Register Bit Bit
A WR14.2 = 1 I/O(4).7
A WR1.6 = 1 I/O(4).7
B WR14.2 = 1 I/O(4).6
B WR1.6 = 1 I/O(4).6
Function
Transmit DMA
Receive or Transmit DMA
Transmit DMA
Receive or Transmit DMA