Received data
UART/
IrDA/CIR
RX FIFO
RX FIFO threshold
DMA
DMA request
device
memory
Reserved for
IrDA
reception
uart-031
Public Version
UART/IrDA/CIR Functional Description
www.ti.com
Figure 19-30. Reception Process
1. Enable the reception.
2. Received data are put in the RX FIFO.
3. Data are transferred from the RX FIFO to the device memory by the DMA.
•
At each received byte, the RX FIFO trigger level (one character) is reached and a DMA request is
generated.
•
An element (1 byte) is transferred from the RX FIFO to the SDRAM at each DMA request (DMA
element synchronization).
4. The end of the reception is signaled by the EOF interrupt.
19.4.3 Mode Selection
19.4.3.1 Register Access Modes
19.4.3.1.1 Operational Mode and Configuration Modes
Register access depends on the register access mode, although register access modes are not correlated
to functional mode selection. Three different modes are available:
•
Operational mode
•
Configuration mode A
•
Configuration mode B
Operational mode is the selected mode when the function is active; serial data transfer can be performed
in this mode.
Both 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 in the initialization step or
reconfiguration of the module.
The value of the UARTi.
register determines the register access mode (see
Table 19-21. UART/IrDA/CIR Register Access Mode Programming (Using LCR_REG)
Mode
Condition
Configuration_mode_A
[7] = 0x1 and
[7:0]! = 0xBF
Configuration_mode_B
[7] = 0x1 and
[7:0] = 0xBF
Operational_mode
[7] = 0x0
19.4.3.1.2 Register Access Submode
In each access register mode (operational mode or configuration mode A/B), some register accesses are
conditional to the programming of a submode (MSR_SPR, TCR_TLR, and XOFF). These registers are
identified in
, UART/IrDA/CIR Register Manual.
2898
UART/IrDA/CIR
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated