SIO1007 Datasheet, PDF (74/108 Pages) Microchip Technology – LPC Super I/O LPC IrDA Hot Docking Chip with UART

SIO1007
18.4.36 CR25
CR25 can only be accessed in the configuration state and after the CSR has been initialized to 25H. CR25 is used to
select the base address of Serial Port 2 (UART2). Serial Port 2 can be set to 96 locations on 8-byte boundaries from
100H - 3F8H. To disable Serial Port 2, set ADR9 and ADR8 to zero. Set CR25.0 to 0 when writing the UART2 Base
Address.
Serial Port 2 Address Decoding: address bits A[15:10] must be ‘000000’ to access UART2 registers. A[2:0] are decoded
as XXXb.
TABLE 18-30: CR25
Type: R/W
BIT NO.
0
1
2
3
4
5
6
7
BIT NAME
Reserved
ADR3
ADR4
ADR5
ADR6
ADR7
ADR8
ADR9
UART2 Base Address Register
Default: 0X00 ON VCC POR
DESCRIPTION
Read Only. A read returns 0.
Serial Port 2 Base Address bits for decoder.
18.4.37 CR26
Register CR26 is reserved. The default value of this register after power up is 00H.
18.4.38 CR27
Register CR27 is reserved. The default value of this register after power up is 00H.
18.4.39 CR28
CR28 can only be accessed in the configuration state and after the CSR has been initialized to 28H. CR28 is used to
select the IRQ for Serial Port 1 (bits 7 - 4) and for Serial Port 2 (bits 3 - 0). The four bit IRQ encoding field is defined in
Table 18-32, "IRQ Encoding". Any unselected IRQ output (registers CR28 - CR2A) is in tristate. Shared IRQs are not
supported in the SIO1007.
TABLE 18-31: CR28
UART Interrupt Selection
Type: R/W
Default: 0X00 ON VCC POR
BIT NO.
3:0
7:4
BIT NAME
UART2 IRQ Select
UART1 IRQ Select
DESCRIPTION
These bits are used to select IRQ for Serial Port 2. See Table 18-32.
These bits are used to select IRQ for Serial Port 1. See Table 18-32.
TABLE 18-32: IRQ ENCODING
Bits [3:0] Or Bits [7:4]
0000
0001
0010
0011
0100
0101
NONE
IRQ_1
IRQ_2
IRQ_3
IRQ_4
IRQ_5
IRQ Selected
DS00002020A-page 74
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