TWR-56F8400 User’s Manual
Page 9 of 35
Table 2.
J9 – TXD Source Select Header
J9 – TXD Source Select Header
Pin #
Connected Signal
Description
1
ELEV_TXD0 at J500A pin A42
Shunt pins 1 and 2 together to connect the DSC
TXDO pin to the primary Tower Connector TXD0
pin. (This is a default position.)
2
GPIOC2/TXD0/TB0/XB_IN2/CLKO
from the 56F84789 DSC – pin 5 (TXD0
function)
3
TXD_SEL to the USB bridge function
on the OSBDM/OSJTAG MCU.
Shunt pins 2 and 3 together to connect the DSC
TXD0 pin to the USB serial bridge function.
Shunt pin 3 and 4 together to connect the DSC
TXD1 pin to the USB serial bridge function.
4
GPIOF4/TXD1/XB_OUT4 from the
56F84789 DSC – pin 41 (TXD1
function)
5
ELEV_TXD1 at J500 pin A44
Shunt pins 4 and 5 together to connect the DSC
TXD1 pin to the primary Tower Connector TXD1
pin. (This is a default position.)
As can be seen in the tables the 56F84789 DSC serial signals may be connected to either the Tower
serial signals or to the USB bridge chip; however, only one channel may be connected to the USB
bridge chip. If the associated 56F84789 DSC serial pins are not being used for the serial functions the
shunts should be removed from those pins. For more information on the USB Serial Bridge function see
section 2.4.2 USB Serial Bridge Interface.
2.3.3
LEDs Controlled by the MC56F84789 DSC
There are nine LEDs with buffers connected to the MC56F84789 DSC. Inverting buffers (U500A-F and
U502D-F) isolate the LEDs from the DSC pins by providing high impedance inputs. The LEDs are
powered by the P3_3V rail and draw about 5mA each. Table 3 shows the DSC pin names associated
with each LED.
Table 3.
LEDs Controlled by the MC56F84789 DSC
LEDs Controlled by the MC56F84789 DSC
MC56F84789 DSC
Pin Name
MC56F84789
Pin Number
LED
Reference
LED
Label
LED
Color
GPIOE0/PWMA_0B
68
D1
E0
Green
GPIOE1/PWMA_0A
69
D2
E1
Yellow
GPIOE2/PWMA_1B
74
D3
E2
Green
GPIOE3/PWMA_1A
75
D4
E3
Yellow
