CY8C3245LTI-144T Datasheet, PDF (43/128 Pages) Cypress Semiconductor – Programmable System-on-Chip (PSoC®)

PSoC^® 3: CY8C32 Family Data Sheet
6.4.5 Pin Interrupts
All GPIO and SIO pins are able to generate interrupts to the
system. All eight pins in each port interface to their own Port
Interrupt Control Unit (PICU) and associated interrupt vector.
Each pin of the port is independently configurable to detect rising
edge, falling edge, both edge interrupts, or to not generate an
interrupt.
Depending on the configured mode for each pin, each time an
interrupt event occurs on a pin, its corresponding status bit of the
interrupt status register is set to “1” and an interrupt request is
sent to the interrupt controller. Each PICU has its own interrupt
vector in the interrupt controller and the pin status register
providing easy determination of the interrupt source down to the
pin level.
Port pin interrupts remain active in all sleep modes allowing the
PSoC device to wake from an externally generated interrupt.
While level sensitive interrupts are not directly supported;
Universal Digital Blocks (UDB) provide this functionality to the
system when needed.
6.4.6 Input Buffer Mode
GPIO and SIO input buffers can be configured at the port level
for the default CMOS input thresholds or the optional LVTTL
input thresholds. All input buffers incorporate Schmitt triggers for
input hysteresis. Additionally, individual pin input buffers can be
disabled in any drive mode.
6.4.7 I/O Power Supplies
Up to four I/O pin power supplies are provided depending on the
device and package. Each I/O supply must be less than or equal
to the voltage on the chip’s analog (VDDA) pin. This feature
allows users to provide different I/O voltage levels for different
pins on the device. Refer to the specific device package pinout
to determine VDDIO capability for a given port and pin.
The SIO port pins support an additional regulated high output
capability, as described in Adjustable Output Level.
6.4.8 Analog Connections
These connections apply only to GPIO pins. All GPIO pins may
be used as analog inputs or outputs. The analog voltage present
on the pin must not exceed the VDDIO supply voltage to which
the GPIO belongs. Each GPIO may connect to one of the analog
global busses or to one of the analog mux buses to connect any
pin to any internal analog resource such as ADC or comparators.
In addition, one select pin provides direct connection to the high
current DAC.
6.4.9 CapSense
This section applies only to GPIO pins. All GPIO pins may be
used to create CapSense buttons and sliders. See the
“CapSense” section on page 61 for more information.
6.4.10 LCD Segment Drive
This section applies only to GPIO pins. All GPIO pins may be
used to generate Segment and Common drive signals for direct
glass drive of LCD glass. See the “LCD Direct Drive” section on
page 60 for details.
6.4.11 Adjustable Output Level
This section applies only to SIO pins. SIO port pins support the
ability to provide a regulated high output level for interface to
external signals that are lower in voltage than the SIO’s
respective VDDIO. SIO pins are individually configurable to
output either the standard VDDIO level or the regulated output,
which is based on an internally generated reference. Typically
the voltage DAC (VDAC) is used to generate the reference (see
Figure 6-13). The “DAC” section on page 61 has more details on
VDAC use and reference routing to the SIO pins. Resistive
pull-up and pull-down drive modes are not available with SIO in
regulated output mode.
6.4.12 Adjustable Input Level
This section applies only to SIO pins. SIO pins by default support
the standard CMOS and LVTTL input levels but also support a
differential mode with programmable levels. SIO pins are
grouped into pairs. Each pair shares a reference generator block
which, is used to set the digital input buffer reference level for
interface to external signals that differ in voltage from VDDIO.
The reference sets the pins voltage threshold for a high logic
level (see Figure 6-13). Available input thresholds are:
 0.5 VDDIO
 0.4 VDDIO
 0.5 VREF
 VREF
Typically the voltage DAC (VDAC) generates the V_REF
reference. The “DAC” section on page 61 has more details on
VDAC use and reference routing to the SIO pins.
Figure 6-13. SIO Reference for Input and Output
Input Path
Digital
Input
Vinref
SIO_Ref
Output Path
Reference
Generator
Voutref
Driver
Vhigh
PIN
Digital
Output
Drive
Logic
Document Number: 001-56955 Rev. *Y
Page 43 of 128