CLUn
Carry from CLU[n-1]
(CLU3 carries to CLU0)
ALTCLK0
ALTCLK1
Clock
Selection
Carry to CLU[n+1]
Output
Selection
CLUnOUT
Look
Up
Table
(LUT)
Clock
Polarity
Synchronizer
FNSEL
OEN
CnEN
CnOUT
Synchronous
Output
(to peripherals)
Asynchronous Output
(to other CLUs)
External Pins
CLU Asynch Outputs
Input Mux A
Timer Overflow Pulses
PCA Channels
External Pins
CLU Asynch Outputs
Input Mux B
ADC0 ADBUSY Flag
PCA Channels
SYSCLK
RST
D
Q
Q
CLR
CnEN
CnEN
CnEN
CE
CnEN
CnOUTa
CMP Asynch Outputs
CMP Asynch Outputs
SPI MISO
SPI MOSI
UART1 TX
Figure 14.2. Individual CLU Block Diagram
14.2 Features
The key features of the Configurable Logic block are as follows:
• Four configurable logic units (CLUs), with direct-pin and internal logic connections
• Each unit supports 256 different combinatorial logic functions (AND, OR, XOR, muxing, etc.) and includes a clocked flip-flop for syn-
chronous operations
• Units may be operated synchronously or asynchronously
• May be cascaded together to perform more complicated logic functions
• Can operate in conjunction with serial peripherals such as UART and SPI or timing peripherals such as timers and PCA channels
• Can be used to synchronize and trigger multiple on-chip resources (ADC, DAC, Timers, etc.)
• Asynchronous output may be used to wake from low-power states
EFM8UB3 Reference Manual
Configurable Logic Units (CLU0, CLU1, CLU2, CLU3)
silabs.com
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