PSoC is a technology developed by Cypress Semiconductor. The acronym stands for Programmable System on Chip. It combines an 8-bit microcontroller with many different output devices on the same chip.
PSoC is used for mixed signal controlling. It can handle both analog and digital inputs, as well as inputs through a great many digital interfaces. Each of these devices may be used without significant burden on the microcontroller.
PSoC has recently been upgraded with a module called CapSense. It provides a no-overhead method of sensing capacitance on nodes connected to the PSoC. This is incredibly useful, especially for touch applications, such as sealed cell phone buttons and advanced touchscreen applications.
CapSense is perhaps one of the more interesting capabilities for new PSoC Devices, and has already been implemented in several cell phone designs. This is because the human body is mostly water.
The capacitance of a capacitor is directly related to the dielectric constant of the material between the two plates of the capacitor. The human body, because it is mostly water, has a high dielectric constant, much higher than that of air.
This means that, by placing two 'plates' under the plastic skin of a cell phone, the PSoC device can tell whn your finger is close to the location of the plates. A button graphic is printed on the plastic above this location. Thus, to 'press' the button, you only need to bring your finger close to the location of the 'button,' and need not press down ona mechanical button.
This allows cell phone makers to make a completely sealed phone with no moving mechanical parts. This allows cell phones to be smaller, lighter, and more reliable.
More specific information on PSoC may be found at the Cypress Semiconductor website: www.cypress.com