A N 1 7 2
10
Rev. 0.4
6.9. VREF Connector (J22)
The VREF jumper block, J22, can be used to connect the VREF (Voltage Reference) output of the C8051F020 to
any (or all) of its voltage reference inputs. Install shorting blocks on J22 in the following manner:
1-2 to connect VREF to VREFD
3-4 to connect VREF to VREF0
5-6 to connect VREF to VREF1
7. Serial Adapter
The Serial Adapter provides the interface between the PC’s RS232 serial port and the C8051F02x’s in-system
debug/programming circuitry. The Serial Adapter connects to the C8051F020 JTAG debug interface on the target
board using the 10-pin connector on the Serial Adapter labeled “JTAG”, see Figure 4. (The Serial Adapter supports
both Silicon Laboratories JTAG and C2 debug interfaces.). All Serial Adapters may be powered from the target
board, but the EC1 and EC2 Serial Adapter units cannot provide power to the target board. Table 7 shows the pin
definitions for the Serial Adapter’s JTAG connector.
Notes:
1.
When powering the Serial Adapter via the JTAG connector, the input voltage to the JTAG connector’s
power pin must be 3.0 to 3.6 VDC. Otherwise, the Serial Adapter must be powered directly by connecting
the AC/DC adapter to the Serial Adapter’s DC power jack.
2.
The Serial Adapter requires a target system clock of 32 Khz or greater.
Pin #
Description
1
3.0 to 3.6 VDC Input
2
GND (Ground)
4
TCK (C2DAT)
5
TMS
6
TDO
7
TDI (C2CLK)
3,8,9,10
Not Connected
Table 7. JTAG/DEBUG Connector Pin Descriptions
Pin 1
Serial
Adapter
Pin 2
JTA
G
Pw
r
Run/
Sto
p
RS232
Figure 4. Serial Adapter JTAG/DEBUG Connector
