Si5324
Preliminary Rev. 0.3
15
21
CS_CA
I/O
LVCMOS
Input Clock Select/Active Clock Indicator.
Input
: In manual clock selection mode, this pin functions as the
manual input clock selector if the
CKSEL_PIN
is set to 1.
0 = Select CKIN1.
1 = Select CKIN2.
If
CKSEL_PIN
= 0, the
CKSEL_REG
register bit controls this func-
tion and this input tristates. If configured for input, must be tied high
or low.
Output
: In automatic clock selection mode, this pin indicates which
of the two input clocks is currently the active clock. If alarms exist on
both clocks, CK_ACTV will indicate the last active clock that was
used before entering the digital hold state. The
CK_ACTV_PIN
reg-
ister bit must be set to 1 to reflect the active clock status to the
CK_ACTV output pin.
0 = CKIN1 active input clock.
1 = CKIN2 active input clock.
If
CK_ACTV_PIN
= 0, this pin will tristate. The CK_ACTV status will
always be reflected in the
CK_ACTV_REG
read only register bit.
22
SCL
I
LVCMOS
Serial Clock.
This pin functions as the serial clock input for both SPI and I
2
C
modes.
This pin has a weak pull-down.
23
SDA_SDO
I/O
LVCMOS
Serial Data.
In I
2
C control mode (CMODE = 0), this pin functions as the bidirec-
tional serial data port.
In SPI control mode (CMODE = 1), this pin functions as the serial
data output.
25
24
A1
A0
I
LVCMOS
Serial Port Address.
In I
2
C control mode (CMODE = 0), these pins function as hardware
controlled address bits. The I
2
C address is 1101 [A2] [A1] [A0].
In SPI control mode (CMODE = 1), these pins are ignored.
These pins have a weak pull-down.
26
A2_SS
I
LVCMOS
Serial Port Address/Slave Select.
In I
2
C control mode (CMODE = 0), this pin functions as a hardware
controlled address bit [A2].
In SPI control mode (CMODE = 1), this pin functions as the slave
select input.
This pin has a weak pull-down.
27
SDI
I
LVCMOS
Serial Data In.
In I
2
C control mode (CMODE = 0), this pin is ignored.
In SPI control mode (CMODE = 1), this pin functions as the serial
data input.
This pin has a weak pull-down.
Pin #
Pin Name
I/O
Signal Level
Description
Note:
Internal register names are indicated by underlined italics, e.g.,
INT_PIN
. See Si5324 Register Map.