Specifications GAL20V8

9

Combinatorial Output with Feedback Configuration

for Simple Mode

- SYN=1.

- AC0=0.

- XOR=0 defines Active Low Output.

- XOR=1 defines Active High Output.

- AC1=0 defines this configuration.

- All OLMC except pins 18 & 19 can be configured to

this function.

Combinatorial Output Configuration for Simple Mode

- SYN=1.

- AC0=0.

- XOR=0 defines Active Low Output.

- XOR=1 defines Active High Output.

- AC1=0 defines this configuration.

- Pins 18 & 19 are permanently configured to this

function.

Dedicated Input Configuration for Simple Mode

- SYN=1.

- AC0=0.

- XOR=0 defines Active Low Output.

- XOR=1 defines Active High Output.

- AC1=1 defines this configuration.

- All OLMC except pins 18 & 19 can be configured to

this function.

Note: The development software configures all of the architecture control bits and checks for proper pin usage automatically.

In the Simple mode, pins are configured as dedicated inputs or as

dedicated, always active, combinatorial outputs.

Architecture configurations available in this mode are similar to the

common 14L8 and 16P6 devices with many permutations of ge-

neric output polarity or input choices.

All outputs in the simple mode have a maximum of eight product

terms that can control the logic. In addition, each output has pro-

grammable polarity.

Pins 1 and 13 are always available as data inputs into the AND

array. The “center” two macrocells (pins 18 and 19) cannot be used

in the input configuration.

The JEDEC fuse numbers including the UES fuses and PTD fuses

are shown on the logic diagram on the following page.

Vcc

XOR

Vcc

XOR

Simple Mode