Functional Description
Configuration mode A and configuration mode B are used during module initialization steps. These modes
enable access to configuration registers, which are hidden in the operational mode. The modes are used
when the module is inactive (no serial data transfer processed) and only for initialization or reconfiguration
of the module.
The value of the UARTi.UART_LCR register determines the register access mode (see
).
Table 19-16. UART/IrDA/CIR Register Access Mode Programming (Using UART_LCR)
Mode
Condition
Configuration mode A
UART_LCR[7] = 0x1 and UART_LCR[7:0] != 0xBF
Configuration mode B
UART_LCR[7] = 0x1 and UART_LCR[7:0] = 0xBF
Operational mode
UART_LCR[7] = 0x0
19.3.7.1.2 Register Access Submode
In each access register mode (operational mode or configuration mode A/B), some register accesses are
conditional on the programming of a submode (MSR_SPR, TCR_TLR, and XOFF).
through
summarize the register access submodes.
Table 19-17. Subconfiguration Mode A Summary
Mode
Condition
MSR_SPR
(UART_EFR[4] = 0x0 or UART_MCR[6] = 0x0)
TCR_TLR
UART_EFR[4] = 0x1 and UART_MCR[6] = 0x1
Table 19-18. Subconfiguration Mode B Summary
Mode
Condition
TCR_TLR
UART_EFR[4] = 0x1 and UART_MCR[6] = 0x1
XOFF
(UART_EFR[4] = 0x0 or UART_MCR[6] = 0x0)
Table 19-19. Suboperational Mode Summary
Mode
Condition
MSR_SPR
UART_EFR[4] = 0x0 or UART_MCR[6] = 0x0
TCR_TLR
UART_EFR[4] = 0x1 and UART_MCR[6] = 0x1
19.3.7.1.3 Registers Available for the Register Access Modes
lists the names of the register bits in each access register mode. Gray shading indicates that
the register does not depend on the register access mode (available in all modes).
Table 19-20. UART/IrDA/CIR Register Access Mode Overview
Address
Registers
Offset
Configuration Mode A
Configuration Mode B
Operational Mode
Read
Write
Read
Write
Read
Write
0x000
UART_DLL
UART_DLL
UART_DLL
UART_DLL
UART_RHR
UART_THR
0x004
UART_DLH
UART_DLH
UART_DLH
UART_DLH
UART_IER
UART_IER
0x008
UART_IIR
UART_FCR
UART_EFR
UART_EFR
UART_IIR
UART_FCR
0x00C
UART_LCR
UART_LCR
UART_LCR
UART_LCR
UART_LCR
UART_LCR
0x010
UART_MCR
UART_MCR
UART_XON1_ADD
UART_XON1_AD
UART_MCR
UART_MCR
R1
DR1
3468Universal Asynchronous Receiver/Transmitter (UART)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated