C2 Interface; C2 Pin Sharing; Figure 35.1. 10-Pin C2 Usb Debugging Adapter Connection To Device - Silicon Laboratories Si4010-C2 Manual

Si4010-C2

35. C2 Interface

The devices include an on-chip Silicon Laboratories 2-Wire (C2) debug interface in-system debugging with
the production part installed in the end application. The C2 interface uses a clock signal (C2CLK) and a bi-
directional C2 data signal (C2DAT) to transfer information between the device and a host system. The C2
interface is intended to be used by the Silicon Labs or third party development tools. It is not intended to be
used for any other purpose. It can be completely disabled per user programming for fully programmed
chips.

35.1. C2 Pin Sharing

The C2 protocol allows the C2 pins to be shared with user functions so that in-system debugging. This is
possible because C2 communication is typically performed when the device is in the halt state, where all
on-chip peripherals and user software are stalled. In this halted state, the C2 interface can safely borrow
the C2CLK (GPIO[5]) and C2DAT (GPIO[4]) pins. In most applications, external resistors are required to
isolate C2 interface traffic from the user application. A typical isolation configuration is shown in
Figure 35.1 along with the connection to the standard Silicon Labs 10-pin debugging interface header.
For debugging chain to
work, LED must be
isolated by R6
1k
TMS
R4
C2CLK

Figure 35.1. 10-pin C2 USB Debugging Adapter Connection to Device

148
If pushbutton on keyfob
development board, then it
has to be isolated by R5
SW_GPIO4
R5
1k5
VDD
LED
R6 470
USB debug adapter
10 pin header connector
1 2
3 4
5 6
7 8
1k
9 10
1k
R2
For application bidirectional use,
isolated from the C2
Rev. 1.0
VDD
VDD
50k
GPIO4
C2DAT
Device
VDD
50k
GPIO5
C2CLK
1mA max
R1
VBUS (~ +4.6V) Can be used to
generate local VDD
GPIO[4]