Specifications

PL 3120/PL 3150/ PL 3170 Power Line Smart Transceiver Data Book 59
Serial I/O Objects
The timing numbers shown in this section are valid for both an explicit I/O call or an implicit I/O call through a when
clause, and are assumed to be for a PL Smart Transceiver running at 10MHz.
Bitshift Input/Output
Pairs of adjacent pins can be configured as serial input or output lines. The first pin of the pair can be IO0-IO6, IO8, or
IO9, and is used for the clock (driven by the PL Smart Transceiver). The adjacent higher-numbered I/O pin is then used
for up to 16 bits of serial data. The bit rate can be configured as 1kbps, 10kbps, or 15kbps at a 10MHz input clock rate.
The bit rate scales proportionally to the input clock rate. The active clock edge can be specified as either rising or
falling. This object is useful for transferring data to external logic employing shift registers. This function suspends
application processing until the operation is complete (see Figures 3.21, 3.22, and 3.23).
Figure 3.21 Bitshift I/O Examples
For bitshift input, the clock output is deasserted (to the inactive level) at the same time as the start of the first bit of data.
For bitshift output, the clock output is initially inactive prior to the first bit of data (unless overridden by a bit output
overlay).
BITSHIFT OUTPUT
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
Clk
Data
Clk
Clk
Data
Clk
Data
Data
Clk
Data
BITSHIFT INPUT
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
Clk
Data
Clk
Clk
Data
Clk
Data
Data
Clk
Data
IO11 IO11