CY8C34_11 Datasheet, PDF (56/126 Pages) Cypress Semiconductor – Programmable System-on-Chip (PSoC®)

PSoC^® 3: CY8C34 Family
Data Sheet
8.3.2 LUT
The CY8C34 family of devices contains four LUTs. The LUT is a
two input, one output lookup table that is driven by any one or
two of the comparators in the chip. The output of any LUT is
routed to the digital system interface of the UDB array. From the
digital system interface of the UDB array, these signals can be
connected to UDBs, DMA controller, I/O, or the interrupt
controller.
The LUT control word written to a register sets the logic function
on the output. The available LUT functions and the associated
control word is shown in Table 8-2.
The opamp is uncommitted and can be configured as a gain
stage or voltage follower, or output buffer on external or internal
signals.
See Figure 8-8. In any configuration, the input and output signals
can all be connected to the internal global signals and monitored
with an ADC, or comparator. The configurations are
implemented with switches between the signals and GPIO pins.
Figure 8-8. Opamp Configurations
a) Voltage Follower
Table 8-2. LUT Function vs. Program Word and Inputs
Control Word
0000b
0001b
0010b
0011b
0100b
0101b
0110b
0111b
1000b
1001b
1010b
1011b
1100b
1101b
1110b
1111b
Output (A and B are LUT inputs)
FALSE (‘0’)
A AND B
A AND (NOT B)
A
(NOT A) AND B
B
A XOR B
A OR B
A NOR B
A XNOR B
NOT B
A OR (NOT B)
NOT A
(NOT A) OR B
A NAND B
TRUE (‘1’)
8.4 Opamps
The CY8C34 family of devices contains two general purpose
opamps in a device.
Figure 8-7. Opamp
GPIO
Analog
Global Bus
Analog
Global Bus
VREF
Analog
Internal Bus
GPIO
Opamp
GPIO
= Analog Switch
Opamp
Vin
Vout to Pin
b) External Uncommitted
Opamp
Opamp
Vout to GPIO
c) Internal Uncommitted
Opamp
Vn
To Internal Signals
Vp
Opamp
Vp to GPIO
Vn to GPIO
Vout to Pin
GPIO Pin
The opamp has three speed modes, slow, medium, and fast. The
slow mode consumes the least amount of quiescent power and
the fast mode consumes the most power. The inputs are able to
swing rail-to-rail. The output swing is capable of rail-to-rail
operation at low current output, within 50 mV of the rails. When
driving high current loads (about 25 mA) the output voltage may
only get within 500 mV of the rails.
8.5 Programmable SC/CT Blocks
The CY8C34 family of devices contains two switched
capacitor/continuous time (SC/CT) blocks in a device. Each
switched capacitor/continuous time block is built around a single
rail-to-rail high bandwidth opamp.
Switched capacitor is a circuit design technique that uses
capacitors plus switches instead of resistors to create analog
functions. These circuits work by moving charge between
Document Number: 001-53304 Rev. *K
Page 56 of 126
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