Cirrus Logic CDB5490U - Manual (Page 9)

CDB5490U
DS923DB5 9
1.4 Digital Section
The digital section contains the microcontroller, USB interface, LCD, optical isolation, JTAG header, reset
circuitry, and external interface headers (J17 and J19). The microcontroller interfaces the UART of the
CS5490 with the USB connection to the PC, enabling the GUI software to access all of the CS5490 reg-
isters and functions.
1.4.1 Serial Port Selection
Communication to the CS5490 is provided through a standard UART. It is necessary to establish commu-
nication with the MCU before serial port communication with the CS5490 (see Figure 5).
The CDB5490U board provides two UART communication options - normal speed and low speed. Table 3
provides the serial communication options for the UART.
Table 3. Serial Communication Options
Figure 5. MCU Connection Window
J18
J20 J50
UART
via MCU
Ƒ OPTO
ż RX
ż DIGITAL
(default)
Ƒ OPTO
ż TX
ż DIGITAL
(default)
Ƒ VDDA
ż EN2
ż GND
(default)
Low speed
UART
Ƒ OPTO
ż RX
ż DIGITAL
Ƒ OPTO
ż TX
ż DIGITAL
Ƒ VDDA
ż EN2
ż GND