C8051T600-GS(2007) View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

MFG CO.

C8051T600-GS
(Rev.:2007)

Mixed Signal OTP EPROM MCU Family

Silicon Laboratories 

C8051T600/1/2/3/4/5

19.2. C2 Pin Sharing

The C2 protocol allows the C2 pins to be shared with user functions so that in-system debugging and

EPROM programming functions may be performed. This is possible because C2 communication is typi-

cally 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 C2CK (normally RST) and C2D (nor-

mally P0.7) pins. In most applications, external resistors are required to isolate C2 interface traffic from the

user application when performing debug functions. These external resistors are not necessary for produc-

tion boards. A typical isolation configuration is shown in Figure 19.1.

/Reset (a)

Input (b)

Output (c)

C2CK (/RST)

C2D (P0.7)

C2 Interface Master

Figure 19.1. Typical C2 Pin Sharing

The configuration in Figure 19.1 assumes the following:

1. The user input (b) cannot change state while the target device is halted.

2. The RST pin on the target device is used as an input only.

Additional resistors may be necessary depending on the specific application.

166

Rev. 0.5

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