ez80f91 ZiLOG Semiconductor, ez80f91 Datasheet - Page 199

• Manufacturer Part Number: ez80f91
• Description: Ez80 Acclaimplus!? Connectivity Assp Ez80f91 Assp
• Manufacturer: ZiLOG Semiconductor

Table 105. UART Modem Control Registers
PS027001-0707
Bit
Reset
CPU Access
Note: R = Read Only; R/W = Read/Write.
Bit
Position
7
6
POLARITY
5
MDM
4
LOOP
3
OUT2
2
OUT1
UART Modem Control Register
This register is used to control and check the modem status. See
Value
0
0
1
0
1
0
1
0–1
0–1
Description
Reserved
TxD and RxD signals—Normal Polarity.
Invert Polarity of TxD and RxD signals.
Multidrop Mode disabled.
Multidrop Mode enabled. See
select definitions.
LOOP BACK mode is not enabled.
LOOP BACK mode is enabled.
The UART operates in internal LOOP BACK mode. The
transmit data output port is disconnected from the internal
transmit data output and set to 1. The receive data input port is
disconnected and internal receive data is connected to internal
transmit data. The modem status input ports are disconnected
and the four bits of the modem control register are connected
as modem status inputs. The two modem control output ports
(OUT1&2) are set to their inactive state
No function in normal operation.
In LOOP BACK mode, this bit is connected to the DCD bit in
the UART Status Register.
No function in normal operation.
In LOOP BACK mode, this bit is connected to the RI bit in the
UART Status Register.
R
7
0
R/W
6
0
R/W
5
0
R/W
(UART0_MCTL = 00C4h, UART1_MCTL = 00D4h)
4
0
Table 104
R/W
3
0
Universal Asynchronous Receiver/Transmitter
on page 189 for parity
R/W
2
0
R/W
1
0
Product Specification
Table
R/W
0
0
105.
eZ80F91 ASSP
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