C8051F331 Silicon Laboratories Inc, C8051F331 Datasheet - Page 205

• Manufacturer Part Number: C8051F331
• Description: IC 8051 MCU 8K FLASH 20MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F331

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

20.2. C2 Pin Sharing
The C2 protocol allows the C2 pins to be shared with user functions so that in-system debugging, Flash
programming, and boundary scan functions may be performed. This is possible because C2 communica-
tion is typically performed when the device is in the halt state, where all on-chip peripherals and user soft-
ware are stalled. In this halted state, the C2 interface can safely ‘borrow’ the C2CK (/RST) and C2D (P2.0)
pins. In most applications, external resistors are required to isolate C2 interface traffic from the user appli-
cation. A typical isolation configuration is shown in Figure 20.6.
The configuration in Figure 20.6 assumes the following:
Additional resistors may be necessary depending on the specific application.
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.
/Reset (a)
Output (c)
Input (b)
Figure 20.6. Typical C2 Pin Sharing
C2 Interface Master
C8051F330/1, C8051F330D
Rev. 1.2
C2CK
C2D
C8051Fxxx
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