Datasheet

71M6543F/71M6543G Data Sheet
v2 57
When not needed for UART1, OPT_TX can alternatively be configured as SEGDIO51. Configuration is
via the OPT_TXE[1:0] (I/O RAM 0x2456[3:2]) field and LCD_MAP[51] (I/O RAM 0x2405[0]). The
OPT_TXE[1:0] field allows the MPU to select VPULSE, WPULSE, SEGDIO51 or the output of the pulse
modulator to be sourced onto the OPT_TX pin. Likewise, the OPT_RX pin can alternately be configured
as SEGDIO55, and its control is OPT_RXDIS (I/O RAM 0x2457[2]) and LCD_MAP[55] (I/O RAM 0x2405[4]).
B
A
OPT_TXMOD = 0
OPT_TXMOD = 1,
OPT_FDC = 2 (25%)
B
A
1/38kHz
OPT_TXINV
from
OPT_TX UART
MOD
EN DUTY
OPT_TX
OPT_TXMOD
OPT_FDC
OPT_TXE[1:0]
0
2
V3P3
Internal
A
B
1
2
3
DIO2
WPULSE
VARPULSE
Figure 14: Optical Interface
Bit Banged Optical UART (Third UART)
As shown in Figure 15, the 71M6543 can also be configured to drive the optical UART with a DIO signal
in a bit banged configuration. When control bit OPT_BB (I/O RAM 0x2022[0]) is set, the optical port is
driven by DIO5 and the SEGDIO5 pin is driven by UART1_TX. This configuration is typically used when
the two dedicated UARTs must be connected to high speed clients and a slower optical UART is
permissible.
OPT_TXINV
UART1_TX
MOD
EN DUTY
SEGDIO51/
OPT_TX
OPT_TXMOD
OPT_FDC
OPT_TXE[1:0]
0
2
V3P3
Internal
A B
OPT_TXMOD=0
OPT_TXMOD=1,
OPT_FDC=2 (25%)
B
A
1/38kHz
1
2
3
DIO51
WPULSE
VARPULSE
SEG51
LCD_MAP[51]
1
0
SEGDIO55/
OPT_RX
SEG55
LCD_MAP[55]
1
0
DIO55
1
0
OPT_RXDIS
UART1_RX
DIO5
SEGDIO5/TX2
SEG5
1
0
LCD_MAP[5]
OPT_BB
0
0
1
1
Figure 15: Optical Interface (UART1)
2.5.10 Digital I/O and LCD Segment Drivers
2.5.10.1 General Information
The 71M6543 combines most DIO pins with LCD segment drivers. Each SEG/DIO pin can be configured
as a DIO pin or as a segment driver pin (SEG).
On reset or power-up, all DIO pins are DIO inputs (except for SEGDIO0-15, see caution note below) until
they are configured as desired under MPU control. The pin function can be configured by the I/O RAM