locations, on 8 byte boundaries from 100H-
3F8H. To disable the serial port, set ADR9
and ADR8 to zero.
CR24
This register can only be accessed in the
Configuration Mode and after the CSR has been
initialized to 25H. The default value of this
register after power up is 00H. This register is
used to select the base address of UART1
(serial port 1). The serial port can be set to 96
Upper Address Decode requirements : nCS='0'
and A10='0' are required to access UART1
registers. A[2:0] are decoded as XXXb.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
ADR9
ADR8
ADR7
ADR6
ADR5
ADR4
ADR3
0
locations, on 8 byte boundaries from 100H-
3F8H. To disable the serial port, set ADR9
and ADR8 to zero.
CR25
This register can only be accessed in the
Configuration Mode and after the CSR has been
initialized to 25H. The default value of this
register after power up is 00H. This register is
used to select the base address of UART2
(serial port 2). The serial port can be set to 96
Upper Address Decode requirements : nCS='0'
and A10='0' are required to access UART2
registers. A[2:0] are decoded as XXXb.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
ADR9
ADR8
ADR7
ADR6
ADR5
ADR4
ADR3
0
register after power up is 00H. This register is
used to select the DMA for the FDC (Bits 4:7)
and the parallel port (bits 3:0). Any unselected
DMA REQ output is in tristate.
CR26
This register can only be accessed in the
Configuration Mode and after the CSR has been
initialized to 26H. The default value of this
D3-D0
D7-D4
DMA Selected
None
0000
0001
0010
0011
DMA_A
DMA_B
DMA_C
134
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