2
XR20M1280 EVALUATION BOARD USER’S MANUAL
REV. 1.0.0
J15
Selects the supply voltage for GPIO15-
GPIO4 (VCC_GPIO)
Not used for XR20M1280IL24
Jumper in 1&2 selects 3.3V (default)
Jumper in 3&4 selects 2.5V
Jumper in 5&6 selects 1.8V
J52
Selects 5V source for regulator to 1.8V
Jumper in 1&2 selects 5V source from J9 pins 34 &36 (default)
Jumper in 2&3 selects 5V source from +P
J53
Selects 5V source for regulator to 2.5V
Jumper in 1&2 selects 5V source from J9 pins 34 &36 (default)
Jumper in 2&3 selects 5V source from +P
J54
Selects 5V source for regulator to 3.3V
Jumper in 1&2 selects 5V source from J9 pins 34 &36 (default)
Jumper in 2&3 selects 5V source from +P
J36
Selects between I
2
C and SPI mode
Jumper in selects SPI mode (default for XR20M1280L24-0B-EB)
Jumper out selects I
2
C mode (default for XR20M1280L24-0A-EB)
J18
Power for the SP337 RS-232/RS-485
Transceiver
Jumper not installed
Trace between 1&2
J19
Header for RS-485/422 signals
RS-485/422 signals are accessible at this header
J20
SP337 Mode Control pins
RS-232 Mode - No jumpers installed
RS-485 Mode - Jumpers between 1&2, 5&6
J34
Routing of modem signals to SP337 RS-
232/RS-485 Transceiver
Trace between 1&2
Trace between 3&4
Trace between 5&6
Trace between 7&8
No trace between 9&10 (jumper installed)
J37
Routing of modem signals to SP337 RS-
232/RS-485 Transceiver
Trace between 1&2
Trace between 3&4
Trace between 5&6
(Pins 7-10 not used for XR20M1280IL24)
J35
Enable/Disable Auto RS-485 mode at
power-up
(can be enabled/disabled in software after
power-up)
J35 in enables Auto RS-485 mode at power-up
J35 out disables Auto RS-485 mode at power-up
J50
SLEEP/PWRDN pin
Header installed, no jumpers installed (default)
Refer to the datasheet for the behavior of this pin
J51
UART Reset input
Jumper on 1&2 selects J2 as hardware reset
Jumper on 2&3 selects external reset from J9 pin 32 (default)
J10
I
2
C Address Select (A0)
■
1&2 = VCC
■
3&4 = SCL
■
5&6 = SDA
■
7&8 = GND
For I
2
C mode, only one jumper should be selected. See
XR20M1280 datasheet for I
2
C addressing.
For SPI mode, jumper should be out.
T
ABLE
3: J
UMPER
S
ETTINGS
F
OR
XR20M1280IL24
J
UMPERS
F
UNCTIONS
C
OMMENTS
