NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
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Revision V1.30
NUC97
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CHNIC
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IrDA SIR Operation
The IrDA SIR Encoder/Decoder provides functionality which converts between UART data stream and
half duplex serial SIR interface. Refer to UA_IRCR register for detail description. The following
diagram shows the IrDA encoder/decoder waveform.
Figure 5.16-9 IrDA TX/RX Timing Diagram
RS-485 Function Mode
5.16.5.7
The UART supports RS-485 9-bit mode function. The RS-485 mode is selected by setting the
FUN_SEL(UA_FUN_SEL[2:0]) to select RS-485 function. The RS-485 driver control is implemented
using the RTS control signal from an asynchronous serial port to enable the RS-485 driver. In RS-485
mode, many characteristics of the RX and TX are same as UART.
In RS-485 mode, the bit 9 will be configured as address bit. The controller can configuration of it as an
RS-485 addressable slave and the RS-485 master transmitter will identify an address character by
setting the parity (9th bit) to 1.
For data characters,
the bit 9 is set to “0”. Software can use UA_LCR register to control the 9-th bit
(When the PBE(UA_LCR[3]), EPE(UA_LCR[4]) and SPE(UA_LCR[5]) are set, the 9-th bit is
transmitted 0 and when PBE and SPE are set and EPE is cleared, the 9-th bit is transmitted 1).
The Controller support three operation mode that is RS-485 Normal Multi-drop Operation Mode
(NMM), RS-485 Auto Address Detection Operation Mode (AAD) and RS-485 Auto Direction Control
Operation Mode (AUD), software can choose any operation mode by programming UA_ALT_CSR
register, and software can driving the transfer delay time between the last stop bit leaving the TX-FIFO
and the de-assertion of by setting DLY(UA_TOR [15:8]).
Another alternate function of UART controllers is RS-485 9 bit mode function whose direction control
can be controlled by RTSn pin or GPIO. The RS-485 function mode is selected by setting the
FUN_SEL(UA_FUN_SEL[2:0]) to select RS-485 function. The RS-485 driver control is implemented
by using the RTSn control signal from an asynchronous serial port to enable the RS-485 driver. In RS-
485 mode, many characteristics of the RX and TX are same as UART.
SOUT
(from uart TX)
IR_SOUT
(encoder output)
IR_SIN
(decorder input)
SIN
(To uart RX)
0
0
1
0
1
1
1
0
0
1
1
0
1
0
0
1
0
1
0
0
1
1
Bit pulse width
3/16 bit width
3/16 bit width
STOP BIT
START BIT
START BIT
STOP BIT
Tx
Timing
Rx
Timing
INV_TX(UA_IRCR[5]) = 0
INV_RX(UA_IRCR[6]) = 1