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Lattice Semiconductor
ORCA ORT8850 Data Sheet
78
Special-Purpose Pins
M[3:0]
I
During power-up and initialization, M0—M3 are used to select the conguration mode with their val-
ues latched on the rising edge of INIT. During conguration, a pull-up is enabled.
I/O After conguration, these pins are user-programmable I/O.*
PLL_CK[0:7][TC]
I
Semi-dedicated PLL clock pins. During conguration they are 3-stated with a pull up.
I/O These pins are user-programmable I/O pins if not used by PLLs after conguration.
P[TBLR]CLK[1:0][T
C]
I
Pins dedicated for the primary clock. Input pins on the middle of each side with differential pairing.
I/O After conguration these pins are user-programmable I/O, if not used for clock inputs.
TDI, TCK, TMS
I
If boundary-scan is used, these pins are test data in, test clock, and test mode select inputs. If
boundary-scan is not selected, all boundary-scan functions are inhibited once conguration is com-
plete. Even if boundary-scan is not used, either TCK or TMS must be held at logic 1 during congu-
ration. Each pin has a pull-up enabled during conguration.
I/O After conguration, these pins are user-programmable I/O in boundary scan is not used.*
RDY/BUSY/RCLK
O
During conguration in asynchronous peripheral mode, RDY/RCLK indicates another byte can be
written to the FPGA. If a read operation is done when the device is selected, the same status is also
available on D7 in asynchronous peripheral mode.
During the master parallel conguration mode, RCLK is a read output signal to an external memory.
This output is not normally used.
I/O After conguration this pin is a user-programmable I/O pin.*
HDC
O
High during conguration is output high until conguration is complete. It is used as a control output,
indicating that conguration is not complete.
I/O After conguration, this pin is a user-programmable I/O pin.*
LDC
O
Low during conguration
is output low until conguration is complete. It is used as a control output,
indicating that conguration is not complete.
I/O After conguration, this pin is a user-programmable I/O pin.*
INIT
I/O
INIT
is a bidirectional signal before and during conguration. During conguration, a pull-up is
enabled, but an external pull-up resistor is recommended. As an active-low open-drain output, INIT
is held low during power stabilization and internal clearing of memory. As an active-low input, INIT
holds the FPGA in the wait-state before the start of conguration.
After conguration, this pin is a user-programmable I/O pin.*
CS0, CS1
I
CS0
and CS1 are used in the asynchronous peripheral, slave parallel, and microprocessor congu-
ration modes. The FPGA is selected when CS0 is low and CS1 is high. During conguration, a pull-
up is enabled.
I/O After conguration, if MPI is not used, these pins are user-programmable I/O pins.*
RD/MPI_STRB
I
RD
is used in the asynchronous peripheral conguration mode. A low on RD changes D[7:3] into a
status output. WR and RD should not be used simultaneously. If they are, the write strobe overrides.
This pin is also used as the
MPI data transfer strobe. As a status indication, a high indicates ready,
and a low indicates busy.
WR/MPI_RW
I
WR is used in asynchronous peripheral mode. A low on WR transfers data on D[7:0] to the FPGA.
In MPI mode, a high on MPI_RW allows a read from the data bus, while a low causes a write trans-
fer to the FPGA.
I/O After conguration, if the MPI is not used, WR/MPI_RW is a user-programmable I/O pin.*
PPC_A[14:31]
I
During MPI mode the PPC_A[14:31] are used as the address bus driven by the
PowerPC bus mas-
ter utilizing the least-signicant bits of the
PowerPC 32-bit address.
MPI_BURST
I
MPI_BURST is driven low to indicate a burst transfer is in progress in MPI mode. Driven high indi-
cates that the current transfer is not a burst.
Table 32. FPGA Common-Function Pin Descriptions (Continued)
Symbol
I/O
Description
1. The FPGA States of Operation section contains more information on how to control these signals during start-up. The timing of DONE
release is controlled by one set of bit stream options, and the timing of the simultaneous release of all other conguration pins (and the activa-
tion of all user I/Os) is controlled by a second set of options.