Cirrus Logic CDB8130 - Manual (Page 6)

CDB8130
6 DS170DB5
Removing J35 will disconnect power from the lev-
el translator.
All the digital signals on the CS8130, FORM/BSY,
D/C, TXD, RXD, EXTCLK, RESET, PWRDN,
and CLKFR can be accessed directly from header
J11. All digital input pins are tied to 47 k
Ω pull-up
resistors through resistor set R1.
1.6 Clock Selection
The clock for the CS8130 can be supplied via a
crystal tied between XTALIN and XTALOUT (the
default configuration on the evaluation board) or
by an external clock supplied through the EXT-
CLK pin.
To operate the CS8130 from an external clock
source, cut the trace under J3 (XTAL), and the
(XTAL) part of J4, then connect the center pin of J4
to the edge pin marked EXT.
Note: the EXTCLK pin on the CS8130 can be ei-
ther an input or an output. If the CS8130 is being
clocked from a crystal, EXTCLK is an output. If
no crystal is present, EXTCLK is an input. This de-
termination of direction is made while RESET is
asserted.
The CS8130 can be operated from either a 3.6864
MHz or a 1.8432 MHz clock source. If operating
from a 3.6864 MHz source, jumper J18 (CLKFR)
must be installed. This brings the CLKFR pin on
the CS8130 low. If operating from a 1.8432 MHz
source, jumper J18 should be removed.
1.7 Power Down
Jumper J14 (PWRDN) controls the state of the
PWRDN pin on the CS8130. PWRDN is asserted
when J14 is installed.
1.8 Status Indicator LEDs
Key digital signals on the CS8130 are displayed on
indicator LEDs U6 (U8) and U7 (U9), shown sche-
matically in Figure 4. Because these LEDs are
driven through inverters, the interpretation of what
it means when a LED is lit can be confusing. Table
2 should help clarify this.
1.9 Software
The CDB8130 evaluation kit comes equipped with
software that can be used to evaluate and test the
CS8130. Additional software is currently under
development.
See the documentation supplied with the CDB8130
evaluation kit for instructions on how to use the
software.
Software updates and new releases can be down-
loaded from the Crystal BBS. Contact the factory
for details.
Name LED On means. . .
LED1C Transmitter #1 active
LED2C Transmitter #2 active
PWRDN Power down asserted
RESET Reset asserted
RXD Data being received by the CS8130
TXD Data being transmitted to the CS8130
D/C CS8130 in Control Mode
FORM/BSY Auto detect ASK/TV TX ready
Table 2. LED Indicator Meanings