CDB8130
Figure 2. Power Supply Circuitry
1.4
RS-232 Interface
The CDB8130 is designed to connect to any stan-
dard RS-232 port through the female DB-9 connec-
tor marked “RS-232.” The MAX562 (U2) supplies
the voltage level translation function, taking the ±
12V RS-232 levels and translating them to standard
CMOS logic levels.
Table 1 shows the default mapping of UART sig-
nals to CS8130 pins.
CS8130 Pin
RXD
UART Signal
RXD
Direction
to UART
Figure 3. Reset Circuit
allows systems using only one LED to operate with
a much higher drive current than can be sourced by
using a single driver. To connect the transmitter
drivers in this way, install jumper J17.
TXD
TXD
to CS8130
to UART
FORM/BSY
D/C
CTS
DTR
to CS8130
to CS8130
RESET
RTS
The LED transmitter driver resistors (R3 and R4)
are optimized for a power supply voltage of 3.3V.
For operation at voltages greater than this, the val-
ues of these resistors must be increased.
Table 1. CS8130-to-UART Connections
1.5
Header Interface
If desired, the RS-232 level translator can be re-
moved from the circuit. The signals are discon-
nected by removing jumpers J5, J6, J7, J8, and J9.
DS170DB5
5
CIRRUS [ CIRRUS LOGIC ]
