CY8C54 CYPRESS [Cypress Semiconductor], CY8C54 Datasheet - Page 51

• Manufacturer Part Number: CY8C54
• Description: Programmable System-on-Chip (PSoC)
• Manufacturer: CYPRESS [Cypress Semiconductor]

and possible resistor settings for the PGA. The gain is switched
from inverting and non inverting by changing the shared select
value of the both the input muxes. The bandwidth for each gain
case is listed in
Table 8-2. Bandwidth
Figure 8-7. PGA Resistor Settings
The PGA is used in applications where the input signal may not
be large enough to achieve the desired resolution in the ADC, or
dynamic range of another SC/CT block such as a mixer. The gain
is adjustable at runtime, including changing the gain of the PGA
prior to each ADC sample.
8.5.4 TIA
The Transimpedance Amplifier (TIA) converts an internal or
external current to an output voltage. The TIA uses an internal
feedback resistor in a continuous time configuration to convert
input current to output voltage. For an input current Iin, the output
voltage is Iin x Rfb +Vref, where Vref is the value placed on the
non inverting input. The feedback resistor Rfb is programmable
between 20 K Ω and 1 M Ω through a configuration register.
Table 8-3
configuration settings.
Table 8-3. Feedback Resistor Settings
Document Number: 001-55036 Rev. *A
V
V
V
V
S
in
ref
ref
in
Configuration Word
Gain
24
48
50
1
0
1
0
1
000b
001b
010b
100b
101b
shows the possible values of Rfb and associated
011b
110b
111b
Table
20k or 40k
R1
8-2.
Bandwidth
6.0 MHz
340 kHz
220 kHz
215 kHz
Nominal R
R2
1000
120
250
500
20
30
40
60
20k to 980k
fb
PRELIMINARY
(
K Ω
)
Figure 8-8. Continuous Time TIA Schematic
The TIA configuration is used for applications where an external
sensor's output is current as a function of some type of stimulus
such as temperature, light, magnetic flux etc. In a common appli-
cation, the voltage DAC output can be connected to the VREF
TIA input to allow calibration of the external sensor bias current
by adjusting the voltage DAC output voltage.
8.6 LCD Direct Drive
The PSoC Liquid Crystal Display (LCD) driver system is a highly
configurable peripheral designed to allow PSoC to directly drive
a broad range of LCD glass. All voltages are generated on chip,
eliminating the need for external components. With a high
multiplex ratio of up to 1/16, the CY8C54 family LCD driver
system can drive a maximum of 736 segments. The PSoC LCD
driver module was also designed with the conservative power
budget of portable devices in mind, enabling different LCD drive
modes and power down modes to conserve power.
PSoC Creator provides an LCD segment drive component. The
component wizard provides easy and flexible configuration of
LCD resources. You can specify pins for segments and
commons along with other options. The software configures the
device to meet the required specifications. This is possible
because of the programmability inherent to PSoC devices.
Key features of the PSoC LCD segment system are:
V ref
LCD panel direct driving
Type A (standard) and Type B (low power) waveform support
Wide operating voltage range support (2V to 5V) for LCD
panels
Static, 1/2, 1/3, 1/4, 1/5 bias voltage levels
Internal bias voltage generation through internal resistor ladder
Up to 62 total common and segment outputs
Up to 1/16 multiplex for a maximum of 16 backplane/common
outputs
Up to 62 front plane/segment outputs for direct drive
Drives up to 736 total segments (16 backplane x 46 front plane)
Up to 128 levels of software controlled contrast
Ability to move display data from memory buffer to LCD driver
through DMA (without CPU intervention)
Adjustable LCD refresh rate from 10 Hz to 150 Hz
I in
PSoC
®
5: CY8C54 Family Data Sheet
R fb
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