Automotive PSoC
®
4: PSoC
4000 Family Datasheet
Document Number: 001-92145 Rev. *E Page 5 of 31
Analog Blocks
Low-power Comparators
The PSoC 4000 has a low-power comparator, which uses the
built-in voltage reference. Any one of up to 16 pins can be used
as a comparator input and the output of the comparator can be
brought out to a pin. The selected comparator input is connected
to the minus input of the comparator with the plus input always
connected to the 1.2-V voltage reference
Current DACs
The PSoC 4000 has two IDACs, which can drive any of up to 16
pins on the chip. These IDACs have programmable current
ranges.
Analog Multiplexed Buses
The PSoC 4000 has two concentric independent buses that go
around the periphery of the chip. These buses (called amux
buses) are connected to firmware-programmable analog
switches that allow the chip's internal resources (IDACs,
comparator) to connect to any pin on Ports 0, 1, and 2.
Fixed Function Digital
Timer/Counter/PWM (TCPWM) Block
The TCPWM block consists of a 16-bit counter with
user-programmable period length. There is a capture register to
record the count value at the time of an event (which may be an
I/O event), a period register that is used to either stop or
auto-reload the counter when its count is equal to the period
register, and compare registers to generate compare value
signals that are used as PWM duty cycle outputs. The block also
provides true and complementary outputs with programmable
offset between them to allow use as dead-band programmable
complementary PWM outputs. It also has a Kill input to force
outputs to a predetermined state; for example, this is used in
motor drive systems when an over-current state is indicated and
the PWM driving the FETs needs to be shut off immediately with
no time for software intervention.
Serial Communication Block (SCB)
The PSoC 4000 has a serial communication block, which imple-
ments a multi-master I
2
C interface.
I
2
C Mode: The hardware I
2
C block implements a full
multi-master and slave interface (it is capable of multi-master
arbitration). This block is capable of operating at speeds of up to
400 kbps (Fast Mode) and has flexible buffering options to
reduce interrupt overhead and latency for the CPU. It also
supports EZI2C that creates a mailbox address range in the
memory of the PSoC 4000 and effectively reduces I
2
C commu-
nication to reading from and writing to an array in memory. In
addition, the block supports an 8-deep FIFO for receive and
transmit which, by increasing the time given for the CPU to read
data, greatly reduces the need for clock stretching caused by the
CPU not having read data on time.
The I
2
C peripheral is compatible with the I
2
C Standard-mode and
Fast-mode devices as defined in the NXP I
2
C-bus specification
and user manual (UM10204). The I
2
C bus I/O is implemented
with GPIO in open-drain modes.
The PSoC 4000 is not completely compliant with the I
2
C spec in
the following respect:
■ GPIO cells are not overvoltage tolerant and, therefore, cannot
be hot-swapped or powered up independently of the rest of the
I
2
C system.
GPIO
The PSoC 4000 has up to 20 GPIOs. The GPIO block imple-
ments the following:
■ Eight drive modes:
❐ Analog input mode (input and output buffers disabled)
❐ Input only
❐ Weak pull-up with strong pull-down
❐ Strong pull-up with weak pull-down
❐ Open drain with strong pull-down
❐ Open drain with strong pull-up
❐ Strong pull-up with strong pull-down
❐ Weak pull-up with weak pull-down
■ Input threshold select (CMOS or LVTTL).
■ Individual control of input and output buffer enabling/disabling
in addition to the drive strength modes
■ Selectable slew rates for dV/dt related noise control to improve
EMI
The pins are organized in logical entities called ports, which are
8-bit in width (less for Ports 2 and 3). During power-on and reset,
the blocks are forced to the disable state so as not to crowbar
any inputs and/or cause excess turn-on current. A multiplexing
network known as a high-speed I/O matrix is used to multiplex
between various signals that may connect to an I/O pin.
Data output and pin state registers store, respectively, the values
to be driven on the pins and the states of the pins themselves.
Every I/O pin can generate an interrupt if so enabled and each
I/O port has an interrupt request (IRQ) and interrupt service
routine (ISR) vector associated with it (4 for PSoC 4000).
Special Function Peripherals
CapSense
CapSense is supported in the PSoC 4000 through a CSD block
that can be connected to up to 16 pins through an analog mux
bus via an analog switch (pins on Port 3 are not available for
CapSense purposes). CapSense function can thus be provided
on any available pin or group of pins in a system under software
control. A PSoC Creator component is provided for the
CapSense block to make it easy for the user.
Shield voltage can be driven on another mux bus to provide
water-tolerance capability. Water tolerance is provided by driving
the shield electrode in phase with the sense electrode to keep
the shield capacitance from attenuating the sensed input.
Proximity sensing can also be implemented.
The CapSense block has two IDACs, which can be used for
general purposes if CapSense is not being used (both IDACs are
available in that case) or if CapSense is used without water
tolerance (one IDAC is available).
