Power and Operation

Page 9

Configuration Devices for SRAM-Based LUT Devices

January 2012

Altera Corporation

configuration bit was sent for the CONF_DONE pin to reach a high state. In this case, the

configuration device pulls its OE pin low, which in turn drives the target device’s

nSTATUS

pin low. Configuration automatically restarts if the Auto-restart

configuration on error

option is turned on in the Quartus II software from the

General

tab of the Device & Pin Options dialog box or the MAX+PLUS II software’s

Global Project Device Options

dialog box (Assign menu).

connections between configuration devices and Altera FPGAs, refer to the

configuration chapter in the appropriate device handbook.

Power and Operation

This section describes power-on reset (POR) delay, error detection, and 3.3-V and

5.0-V operation of Altera configuration devices.

Power-On Reset

During initial power-up, a POR delay occurs to permit voltage levels to stabilize.

When configuring an FPGA with one EPC1, EPC2, or EPC1441 device, the POR delay

occurs inside the configuration device and the POR delay is a maximum of 200 ms.

When configuring a FLEX 8000 device with one EPC1213, EPC1064, or EPC1064V

device, the POR delay occurs inside the FLEX 8000 device and the POR delay is

typically 100 ms, with a maximum of 200 ms.

During POR, the configuration device drives its OE pin low. This low signal delays

configuration because the OEpin is connected to the target FPGA’s nSTATUS pin. When

the configuration device completes POR, it releases its open-drain OE pin, which is

then pulled high by a pull-up resistor.

the master configuration device from entering slave mode.

If the FPGA is not powered up before the configuration device exits POR, the

CONF

_DONE/nCS line is high because of the pull-up resistor. When the configuration

device exits POR and releases OE, it sees nCS high, which signals the configuration

device to enter slave mode. Therefore, configuration will not begin because the DATA

output is tri-stated and DCLK is an input pin in slave mode.

Error Detection Circuitry

The EPC1, EPC2, and EPC1441 configuration devices have built-in error detection

circuitry for configuring ACEX 1K, APEX 20K, APEX II, Arria GX, Cyclone,

Cyclone II, FLEX 10K, FLEX 6000, Mercury, Stratix, Stratix GX, Stratix II, or

Stratix II GX devices.

Built-in error detection circuitry uses the nCS pin of the configuration device, which

monitors the CONF_DONE pin on the FPGA. If the nCS pin on the EPC1 or EPC2 master

device is driven high before all configuration data is transferred, the EPC1 or EPC2

master device drives its OE signal low, which in turn drives the FPGA’s nSTATUS pin

low, indicating a configuration error. Additionally, if the configuration device

generates its data and detects that the CONF_DONE pin has not gone high, it recognizes