Quatech MPAP-100 - Manual (Page 38)

10.3.1 Using channel A for both transmit and receive
This is the mode in which most applications will run. Set RXSRC (bit 1) in the
Configuration Register to logic 0. This will configure the MPAP-100 to use W/REQA for
receive DMA and DTR/REQA for transmit DMA. In addition to any other desired SCC
configuration, ensure that the following bits are set according to Table 6:
Set DTR/REQA for W/REQA timing. 1 4
Assert transmit DMA request when entry location
of internal FIFO is empty.
0 5
WR7A'
Enable WR7A'. 1 0 WR15A
Enable DMA request-on-transmit on
DTR/REQA.
1 2 WR14A
Disable transmit interrupts. 0 1
Enable receive interrupts on special conditions
only (recommended), or disable them completely. 11 or
00
4-3
Use W/REQA for receive. 1 5
Set W/REQA for DMA Request mode. 1 6
Enable DMA request on W/REQA. This bit
should be set after the other bits in WR1 are set as
desired.
1 7
WR1A
Function Value Bit(s) Register
Table 6 --- Configuring the SCC for FIFO use with channel A only