UARTs

the Transmit FIFO will not be held. Only add data to the Transmit FIFO while not receiving. To start transmission, the RCVEIR bit must be cleared.

To disable SIR, disable the IrDA LED first, if possible. Second, set the TXD GPIO pin to the infrared LED's default state using the GPCR/GPSR registers. Next, change the TXD pin from alternate function to GPIO mode. Now the SIR can be disabled without causing spurious transmit pulses.

10.5UART Register Summary

Table 10-18, Table 10-19, and Table 10-20contain the register addresses for the FFUART, BTUART, and STUART.

Table 10-18. FFUART Register Summary

Register Addresses

DLAB Bit

Name

Description

Value

 

 

 

 

 

 

 

0x4010_0000

0

FFRBR

Receive Buffer register (read only)

 

 

 

 

0x4010_0000

0

FFTHR

Transmit Holding register (write only)

 

 

 

 

0x4010_0004

0

FFIER

IER (read/write)

 

 

 

 

0x4010_0008

X

FFIIR

Interrupt ID register (read only)

 

 

 

 

0x4010_0008

X

FFFCR

FCR (write only)

 

 

 

 

0x4010_000C

X

FFLCR

LCR (read/write)

 

 

 

 

0x4010_0010

X

FFMCR

MCR (read/write)

 

 

 

 

0x4010_0014

X

FFLSR

LSR (read only)

 

 

 

 

0x4010_0018

X

FFMSR

MSR (read only)

 

 

 

 

0x4010_001C

X

FFSPR

Scratch Pad Register

 

 

 

 

0x4010_0020

X

FFISR

Infrared Selection register (read/write)

 

 

 

 

0x4010_0000

1

FFDLL

Divisor Latch Low register (read/write)

 

 

 

 

0x4010_0004

1

FFDLH

Divisor Latch High register (read/write)

 

 

 

 

Table 10-19. BTUART Register Summary (Sheet 1 of 2)

Register Addresses

DLAB Bit

Name

Description

Value

 

 

 

 

 

 

 

0x4020_0000

0

BTRBR

Receive Buffer register (read only)

 

 

 

 

0x4020_0000

0

BTTHR

Transmit Holding register (write only)

 

 

 

 

0x4020_0004

0

BTIER

IER (read/write)

 

 

 

 

0x4020_0008

X

BTIIR

Interrupt ID register (read only)

 

 

 

 

0x4020_0008

X

BTFCR

FCR (write only)

 

 

 

 

0x4020_000C

X

BTLCR

LCR (read/write)

 

 

 

 

0x4020_0010

X

BTMCR

MCR (read/write)

 

 

 

 

0x4020_0014

X

BTLSR

LSR (read only)

 

 

 

 

0x4020_0018

X

BTMSR

MSR (read only)

 

 

 

 

10-26

Intel® PXA255 Processor Developer’s Manual

Page 384
Image 384
Intel PXA255 Uart Register Summary, Ffuart Register Summary, Btuart Register Summary Sheet 1, Dlab Bit Name Description