Specifications

PL 3120/PL 3150/ PL 3170 Power Line Smart Transceiver Data Book 39

Hardware Considerations

Tables 3.1 through 3.5 list the available I/O objects. Various I/O objects of different types can be used simultaneously.

Figure 3.3 summarizes the pin configuration for each of the I/O objects. For the electrical characteristics of these pins,

refer to the PL 3120/PL 3150 or PL 3170 Smart Transceiver Datasheets. The following sections contain detailed

descriptions of all the I/O objects. The application program can optionally specify the initial values of digital outputs.

Pins configured as outputs can also be read as inputs, returning the value “at the I/O pin”. Pins IO4 – IO7 and IO11 have

optional pull-up current sources that act like pull-up resistors (see Figure 3.1). These are enabled with a Neuron C

compiler directive (#pragma enable_io_pullups). Pins IO0 – IO3 have high sink capability. The others have

standard sink capability. Pins IO0 – IO7 have low-level detect latches. The latency and timing values described later

in this section are typical at 10MHz. The accuracy of these values is ± 10%. Most latency values scale inversely with

clock rate.

The I/O pull-ups are not enabled during the stack initialization and BIST task. I/O pull-ups are only enabled if

#pragma enable_io_pullups is specified in the Neuron C application. If an I/O pin is not used by the

application, it must either be tied high or low on the PC board or left unconnected and configured as a bit output by the

application in order to prevent unnecessary power consumption. This is particularly important for devices with energy

storage power supplies (See Chapter 5 for more information).

Table 3.1 Summary of Direct I/O Objects

I/O Object Applicable I/O Pins Input/Output Value Page

Bit Input IO0 – IO11 0, 1 binary data

Bit Output IO0 – IO11 0, 1 binary data

Byte Input IO0 – IO7 0 – 255 binary data

Byte Output IO0 – IO7 0 – 255 binary data

Leveldetect Input IO0 – IO7 Logic 0 level detected

Nibble Input Any adjacent 4 in IO0 – IO7 0 – 15 binary data

Nibble Output Any adjacent 4 in IO0 – IO7 0 – 15 binary data

Table 3.2 Summary of Parallel I/O Objects

I/O Object Applicable I/O Pins Input/Output Value Page

Muxbus I/O IO0 – IO10 Parallel bidirectional port using

multiplexed addressing

Parallel I/O IO0 – IO10 Parallel bidirectional handshaking

port