Digi NS9750 - Manual (Page 637)

w w w . d i g i e m b e d d e d . c o m 6 1 3
S e r i a l C o n t r o l M o d u l e : U A R T
D21 R/W RL 0 Remote loopback
Provides a remote loopback feature.
When RL is set to 1, the TXD transmit output is connected
to the RXD receive input. The RL field immediately
echoes receive data back as transmit data.
This field is used primarily as a test vehicle for external
data equipment.
D20 R/W LL 0 Local loopback
Provides an internal local loopback feature.
When LL is set to 1, the internal receive data stream is
connected to the TXD output signal. LL connects the
serial channel receiver directly to the serial channel
transmitter.
This field is used primarily as a test vehicle for the serial
channel driver firmware.
D19:18 R/W Not used 00 This field should be written to 0.
D17 R/W DTR 0 Data terminal ready
Controls the state of the external data terminal ready
signal.
Setting DTR to 1 causes the DTR output to go active.
Setting DTR to 0 causes the DTR output to go
inactive.
D16 R/W RTS 0 Request-to-send
Controls the state of the external request to send signal.
Setting RTS to 1 causes the RTS output to go active.
Setting RTS to 0 causes the RTS output to go
inactive.
D15:12 R/W Not used 0x0 This field should be written to 0.
D11:09 R/W RIE 0x00 Receive interrupt enable
0 Disables the interrupt
1 Enables the interrupt
Allows you to enable interrupts for different receive errors
and conditions.
[11] Receive register ready
[10] Receive FIFO half-full
[09] Receive buffer closed
Bits Access Mnemonic Reset Description
Table 367: Serial Channel B/A/C/D Control Register A