User`s manual

9.3.2 Using channel B for receive
The MPAC-100 supplies only limited support for SCC channel B. This mode,
therefore, is not recommended for most applications. Set RXSRC (bit 1) in the
Configuration Register to logic 1. This will configure the MPAC-100 to use W/REQA
for transmit DMA and W/REQB for receive DMA. In addition to any other desired
SCC configuration, ensure that the following bits are set according to Table 7:
Enable receive interrupts on special
conditions only (recommended), or disable
them completely.
11 or
00
4-3
Use W/REQB for receive.15
Set W/REQB for DMA Request mode.
1
6
Enable DMA request on W/REQB. This bit
should be set after the other bits in WR1 are
set as desired.
17
WR1B
Assert transmit DMA request when entry
location of internal FIFO is empty.
05WR7A'
Enable WR7A'.10WR15A
Disable DMA request-on-transmit on
DTR/REQA.
02WR14A
Disable transmit interrupts.
0
1
Use W/REQA for transmit.
0
5
Set W/REQA for DMA Request mode.16
Enable DMA request on W/REQA. This bit
should be set after the other bits in WR1 are
set as desired.
17
WR1A
Function
Value
Bit(s)
Register
Table 7 --- Configuring the SCC for Rx DMA on channel B
Quatech MPAC-100 User's Manual
31