ATF16V8BQ ATMEL Corporation, ATF16V8BQ Datasheet - Page 7

• Manufacturer Part Number: ATF16V8BQ
• Description: High- Performance Flash PLD
• Manufacturer: ATMEL Corporation

Macrocell Configuration
Software compilers support the three different OMC
modes as different device types. Most compilers have the
ability to automatically select the device type, generally
based on the register usage and output enable (OE) usage.
Register usage on the device forces the software to choose
the registered mode. All combinatorial outputs with OE
controlled by the product term will force the software to
choose the complex mode. The software will choose the
simple mode only when all outputs are dedicated combina-
torial without OE control. The different device types can be
used to override the automatic device selection by the soft-
ware. For further details, refer to the compiler software
manuals.
When using compiler software to configure the device, the
user must pay special attention to the following restrictions
in each mode.
In registered mode pin 1 and pin 11 are permanently con-
figured as clock and output enable, respectively. These
pins cannot be configured as dedicated inputs in the regis-
tered mode.
In complex mode pin 1 and pin 11 become dedicated
inputs and use the feedback paths of pin 19 and pin 12
respectively. Because of this feedback path usage, pin 19
and pin 12 do not have the feedback option in this mode.
Registered Configuration for
Registered Mode
Notes:
1.
2.
Pin 1 cotrols common CLK for the registered out-
puts. Pin 11 controls common OE for the registered
outputs. Pin 1 and Pin 11 are permanently config-
ured as CLK and OE.
The development software configures all the archi-
tecture control bits and checks for proper pin usage
automatically.
(1)(2)
In simple mode all feedback paths of the output pins are
routed via the adjacent pins. In doing so, the two inner most
pins (pins 15 and 16) will not have the feedback option as
these pins are always configured as dedicated combinato-
rial output.
ATF16V8B Registered Mode
PAL Device Emulation / PAL Replacement
The registered mode is used if one or more registers are
required. Each macrocell can be configured as either a reg-
istered or combinatorial output or I/O, or as an input. For a
registered output or I/O, the output is enabled by the OE
pin, and the register is clocked by the CLK pin. Eight prod-
uct terms are allocated to the sum term. For a combinato-
rial output or I/O, the output enable is controlled by a
product term, and seven product terms are allocated to the
sum term. When the macrocell is configured as an input,
the output enable is permanently disabled.
Any register usage will make the compiler select this mode.
The following registered devices can be emulated using
this mode:
16R8 16RP8
16R6 16RP6
16R4 16RP4
Combinatorial Configuration for
Registered Mode
Notes:
1.
2.
Pin 1 and Pin 11 are permanently configured as
CLK and OE.
The development software configures all the archi-
tecture control bits and checks for proper pin usage
automatically.
(1)(2)
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