C 8 0 5 1 F 3 3 6 / 7 / 8 / 9
Rev. 0.3
11
5.7. Serial Interface (J3)
A USB-to-UART bridge circuit (U3) and USB connector (P2) are provided on the target board to facilitate serial
connections to UART0 of the C8051F338. The Silicon Labs CP2102 (U3) USB-to-UART bridge provides data
connectivity between the C8051F338 and the PC via a USB port. The TX, RX, RTS and CTS signals of UART0
may be connected to the CP2102 by installing shorting blocks on header J3. The shorting block positions for
connecting each of these signals to the CP2102 are listed in Table 4. To use this interface, the USB-to-UART
device drivers should be installed as described in Section 4.4. "CP210x USB to UART VCP Driver Installation‚" on
page 5.
5.8. Analog I/O (TB1)
Several of the C8051F338 target device’s port pins are connected to the TB1 terminal block. Refer to Table 5 for
the TB1 terminal block connections.
5.9. IDAC Connector (J6)
The C8051F338 target board also features a Current-to-Voltage 1 K
load resistor that may be connected to the
10-bit current-mode Digital-to-Analog Converter (IDAC) output that can be enabled on port pin (P0.1). Install a
shorting block on J6 to connect port pin P0.1 of the target device to the load resistor. If enabled by software, the
IDAC signal is then routed to the J1[2] and TB1[2] connectors.
5.10. C2 Pin Sharing
On the C8051F338, the debug pins C2CK and C2D are shared with the pins /RST and P2.4 respectively. The
target board includes the resistors necessary to enable pin sharing which allow the /RST and P2.4 pins to be used
normally while simultaneously debugging the device. See Application Note “AN124: Pin Sharing Techniques for the
C2 Interface” at
www.silabs.com
for more information regarding pin sharing.
Table 4. Serial Interface Header (J3) Description
Header Pins UART0 Pin Description
J3[5–6]
TX_MCU (P0.4)
J3[7–8]
RX_MCU (P0.5)
J3[9–10]
RTS (P1.1)
J3[11–12]
CTS (P1.2)
Table 5. TB1 Terminal Block Pin Descriptions
Pin #
Description
1
P0.6 / CNVSTR
2
IDAC
3
P1.5
4
P1.4
5
GND (Ground)
6
P0.0 / Vref (Voltage Reference)
