UG-549
ADuCM310 Hardware Reference Manual
Rev. C | Page 186 of 192
In total, 27 GPIO pins are available on each
for the PLA. These include 14 input pins and 13 output pins, which must be
configured in the GPxCON register as PLA pins before using the PLA.
PLA OPERATION
The PLA is configured via a set of user MMRs. The output(s) of the PLA can be routed to the internal interrupt system, to the
PLA_DOUTx MMRs, or to any of the 13 PLA output pins.
The GPIO inputs to the PLA are always connected to their corresponding elements regardless of the setting in GPxCON. This means that
a pin can be used as both a digital output from the
and an input to the PLA at the same time.
A PLA block can have several clock sources for its output flip-flops, or the flip-flops can be individually bypassed. All output flip-flops in the
same block, if not bypassed, share the same clock source. The configuration of the clock sources can be found in the PLA clock select register.
Each PLA element in a block can be connected to other elements in the same block by configuring the output of MUX0 and MUX1. The
configuration of these two multiplexers can be found in the PLA_ELEMn configuration register. A complete list of the possible connections
are available in Table 292 and Table 293.
The four blocks can be interconnected as follows:
•
Output of Element 7 (Block 0 Element 7) can be fed back to the Input 0 of Mux 0 of Element 8 (Block 1 Element 0).
•
Output of Element 15 (Block 1 Element 7) can be fed back to Input 0 of Mux 0 of Element 16 (Block 2 Element 0).
•
Output of Element 23 (Block 2 Element 7) can be fed back to the Input 0 of Mux 0 of Element 24 (Block 3 Element 0).
•
Output of Element 31 (Block 3 Element 7) can be fed back to Input 0 of Mux 0 of Element 0 (Block 0 Element 0).
See Figure 36 for more information.
There are four interrupts available for the PLA. These interrupts can be configured to trigger on the output of any element using the
PLA_IRQ0 and PLA_IRQ1 registers. The interrupts are active high; therefore, the interrupts continue triggering until the output of the
element goes low or until the IRQ is disabled. If an active low interrupt is required, an extra element must be configured as an inverter
and then the interrupt configured to monitor the output of this new element. If an edge triggered interrupt is required, two extra elements
must be used and configured as an edge detector ((A) AND A).