
Lucent Technologies Inc.
53
Data Sheet
June 1999
ORCA Series 2 FPGAs
Special Function Blocks 
(continued) 
Global 3-State Control (TS_ALL)
The TS_ALL block resides in the upper-right corner of 
the FPGA array.
To increase the testability of the ORCA Series FPGAs, 
the global 3-state function (TS_ALL) disables the 
device. The TS_ALL signal is driven from either an 
external pin or an internal signal. Before and during 
configuration, the TS_ALL signal is driven by the input 
pad 
RD_CFG
. After configuration, the TS_ALL signal 
can be disabled, driven from the 
RD_CFG
 input pad, or 
driven by a general routing signal in the upper-right cor-
ner. Before configuration, TS_ALL is active-low; after 
configuration, the sense of TS_ALL can be inverted. 
The following occur when TS_ALL is activated:
1. All of the user I/O output buffers are 3-stated, the 
user I/O input buffers are pulled up (with the pull-
down disabled), and the input buffers are configured 
with TTL input thresholds (OR2CxxA only). 
2. The TDO/RD_DATA output buffer is 3-stated.
3. The 
RD_CFG
, 
RESET
, and 
PRGM
 input buffers remain 
active with a pull-up.
4. The DONE output buffer is 3-stated, and the input 
buffer is pulled-up.
Internal Oscillator
The internal oscillator resides in the lower-left corner of 
the FPGA array. It has output clock frequencies of 
1.25 MHz and 10 MHz. The internal oscillator is the 
source of the internal CCLK used for configuration. It 
may also be used after configuration as a general-
purpose clock signal.
Global Set/Reset (GSRN)
The GSRN logic resides in the lower-right corner of the 
FPGA. GSRN is an invertible, default, active-low signal 
that is used to reset all of the user-accessible latches/
FFs on the device. GSRN is automatically asserted at 
powerup and during configuration of the device. 
The timing of the release of GSRN at the end of config-
uration can be programmed in the start-up logic 
described below. Following configuration, GSRN may 
be connected to the 
RESET
 pin via dedicated routing, 
or it may be connected to any signal via normal routing. 
Within each PFU, individual FFs and latches can be 
programmed to either be set or reset when GSRN is 
asserted. 
The 
RESET
 input pad has a special relationship to 
GSRN. During configuration, the 
RESET
 input pad 
always initiates a configuration abort, as described in 
the FPGA States of Operation section. After configura-
tion, the global set/reset signal (GSRN) can either be 
disabled (the default), directly connected to the 
RESET
input pad, or sourced by a lower-right corner signal. If 
the 
RESET
 input pad is not used as a global reset after 
configuration, this pad can be used as a normal input 
pad.
Start-Up Logic
The start-up logic block is located in the lower right cor-
ner of the FPGA. This block can be configured to coor-
dinate the relative timing of the release of GSRN, the 
activation of all user I/Os, and the assertion of the 
DONE signal at the end of configuration. If a start-up 
clock is used to time these events, the start-up clock 
can come from CCLK, or it can be routed into the start-
up block using lower-right corner routing resources. 
These signals are described in the Start-Up subsection 
of the FPGA States of Operation section.