ISD94100 Series Technical Reference Manual
Sep 9, 2019
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Rev1.09
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UART Modem Control Register (UART_MODEM)
Register
Offset
R/W Description
Reset Value
UART_MODEM
U0x10
R/W UART Modem Control Register
0x0000_0200
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
RTSSTS
Reserved
RTSACTLV
Reserved
7
6
5
4
3
2
1
0
Reserved
RTS
Reserved
Bits
Description
[31:14]
Reserved
Reserved. Any values read should be ignored. When writing to this field always write with
reset value.
[13]
RTSSTS
nRTS Pin Status (Read Only)
This bit mirror from nRTS pin output of voltage logic status.
0 = nRTS pin output is low level voltage logic state.
1 = nRTS pin output is high level voltage logic state.
[12:10]
Reserved
Reserved. Any values read should be ignored. When writing to this field always write with
reset value.
[9]
RTSACTLV
nRTS Pin Active Level
This bit defines the active level state of nRTS pin output.
0 = nRTS pin output is high level active.
1 = nRTS pin output is low level active. (Default)
Note1:
Refer to Figure 6.12-13 and Figure 6.12-14 for UART function mode.
Note2:
Refer to Figure 6.12-15 and Figure 6.12-16 for RS-485 function mode.
Note3:
Before setting this bit, TXRXDIS (UART_FUNCSEL[3]) should be set then waited for
TXRXACT (UART_FIFOSTS[31]) is cleared. When the configuration is done, cleared
TXRXDIS (UART_FUNCSEL[3]) to activate UART controller.
[8:2]
Reserved
Reserved. Any values read should be ignored. When writing to this field always write with
reset value.
[1]
RTS
nRTS (Request-to-send) Signal Control
This bit is direct control internal nRTS signal active or not, and then drive the nRTS pin
output with RTSACTLV bit configuration.
0 = nRTS signal is active.
1 = nRTS signal is inactive.
Note1:
This nRTS signal control bit is not effective when nRTS auto-flow control is enabled
in UART function mode.
Note2:
This nRTS signal control bit is not effective when RS-485 auto direction mode (AUD)
is enabled in RS-485 function mode.