Parallax P2 Edge Module - Datasheet

External Crystal

The internal clock reference is good for very low power applications, but is also fairly

low accuracy.

For applications that require higher accuracy (ex: handling high speed data) an

external clock source is connected to XI/XO.

Typically a crystal would be connected between XI and XO, but an external clock

source could also be connected to XI only, with common options including a clock

source generator, oscillator, or MEMS resonator.

Refer to the AC Characteristics table for further information.

Reset Switch

Reset Switch can be optionally included and is a convenient way to

restart the Propeller 2 during development or in a ﬁnal product.

The switch drives the Propeller 2 reset pin (RESN) to ground, and while

held low, the Propeller 2 remains in a dormant, low-power state.

Note that the RESN pin must always be pulled high (to 3.3 V) with an

external resistor, which is shown in the Minimal Connections diagram.

SPI Flash Boot Memory

SPI Flash Boot Memory Connections

● Refer to all requirements and recommendations for Minimal Connections

● When the Propeller 2 starts up (or is reset) with this circuit, there will be a serial programming window of

100 ms, then automatic boot from SPI ﬂash. If SPI ﬂash boot fails, then a further serial window of 60

seconds will be followed by shutdown.

● Each Propeller 2 ﬁrmware image requires up to 512 KB. A single SPI Flash chip could hold multiple

ﬁrmware images or code snippets, and/or be used for user data. The SPI Flash chip is fully available to

the user program as a general memory area.