UG-498
ADuCM320 Hardware Reference Manual
Rev. C | Page 146 of 196
PLA
PLA FEATURES
integrates a fully programmable logic array (PLA) that consists of four independent but interconnected PLA blocks.
Each block consists of eight PLA elements: Block X Element 0 to Block X Element 7, where X is the block number. Each
four blocks, resulting in a total of 32 PLA elements: Element 0 to Element 31.
PLA OVERVIEW
Each PLA element contains a two-input lookup table that can be configured to generate any logic output function based on two inputs
and a flip-flop.
4
2
0
A
B
LOOKUP
TABLE
3
1
PLA_ELEMn[4:1]
PLA_ELEMn[5]
PLA_ELEMn[10:9]
PLA_ELEMn[8:7]
GPIO INPUT
PLA_ELEMn[6]
PLA_DIN0[n]
PLA_ELEMn[0]
PLA_CLK
BLOCK X ELEMENT 0
BLOCK X ELEMENT 2
BLOCK X ELEMENT 4
BLOCK X ELEMENT 6
1
2
1
THE FIRST SELECTION OF MUX0 IS THE FEEDBACK FROM BLOCK X ELEMENT 0, WHERE X IS THE NUMBER OF THE CURRENT BLOCK.
IF THE FIRST ELEMENT IN THE BLOCK IS BEING CONFIGURED, THEN THE FEEDBACK COMES FROM ANOTHER BLOCK.
SEE THE INTERBLOCK CONNECTION DIAGRAM FOR MORE DETAILS.
2
BLOCK 0 AND BLOCK 1 ARE SET IN THE CORRESPONDING BIT IN THE PLA_DIN0 MMR.
BLOCK X ELEMENT 1
BLOCK X ELEMENT 3
BLOCK X ELEMENT 5
BLOCK X ELEMENT 7
OUTPUT ELEMENT n
WHERE:
BLOCK X IS BLOCK 0 OR BLOCK 1.
PLA_ELEMn IS THE MMR CONTROLING ELEMENT n, n = 0 TO 15.
NC = NO CONNECTION.
1
1176-
124
Figure 25. PLA Element: Block 0 and Block 1
4
2
0
A
B
LOOKUP
TABLE
3
1
PLA_ELEMn[4:1]
PLA_ELEMn[5]
PLA_ELEMn[10:9]
PLA_ELEMn[8:7]
NC
PLA_ELEMn[6]
OUTPUT ELEMENT (n – 16)
PLA_ELEMn[0]
PLA_CLK
BLOCK X ELEMENT 0
BLOCK X ELEMENT 2
BLOCK X ELEMENT 4
BLOCK X ELEMENT 6
1
2
1
THE FIRST SELECTION OF MUX0 IS THE FEEDBACK FROM BLOCK X ELEMENT 0, WHERE X IS THE NUMBER OF THE CURRENT BLOCK.
IF THE FIRST ELEMENT IN THE BLOCK IS BEING CONFIGURED, THEN THE FEEDBACK COMES FROM ANOTHER BLOCK.
SEE THE INTERBLOCK CONNECTION DIAGRAM.
2
FOR BLOCK 2 AND BLOCK 3 THE INPUT COMES FROM THE OUTPUT OF ELEMENT(n – 16),
WHERE n IS THE NUMBER OF THE ELEMENT BEING CONFIGURED.
FOR EXAMPLE, FOR ELEMENT 25 THE INPUT TO MUX 2 COMES FROM ELEMENT 9.
THIS ALLOWS GPIO INPUTS TO BE INDIRECTLY CONNECTED TO ELEMENTS IN BLOCK 2 AND BLOCK 3.
BLOCK X ELEMENT 1
BLOCK X ELEMENT 3
BLOCK X ELEMENT 5
BLOCK X ELEMENT 7
OUTPUT ELEMENT n
WHERE:
BLOCK X IS BLOCK 2 OR BLOCK 3.
PLA_ELEMn IS THE MMR CONTROLING ELEMENT n, n = 16 TO 31.
NC = NO CONNECTION.
11
176-
125
Figure 26. PLA Element: Block 2 and Block 3
In total, 28 GPIO pins are available on each
for the PLA. These include 14 input pins and 14 output pins, which must be
configured in the GPxCON register as PLA pins before using the PLA.