Configuration Handbook - Kamami.pl

Configuring Cyclone FPGAsWhen designing a board for JTAG configuration of Cyclone FPGAs, youshould consider the dedicated configuration pins. Table 13–7 shows howyou should connect these pins during JTAG configuration.Table 13–7. Dedicated Configuration Pin Connections During JTAG ConfigurationSignalnCEnCEOnSTATUSCONF_DONEnCONFIGMSEL0,MSEL1DCLKDATA0DescriptionDrive all Cyclone devices in the chain low by connecting nCE to ground, pulling it down via aresistor, or driving it low by some control circuitry. For devices in a multi-device PS and ASconfiguration chains, connect the nCE pins to ground during JTAG configuration or configurethem via JTAG in the same order as the configuration chain.For all Cyclone devices in a chain, the nCEO pin can be left floating or connected to the nCEpin of the next device. See nCE description above.Pulled to V CC through a 10-kΩ resistor. When configuring multiple devices in the same JTAGchain, pull up each nSTATUS pin to V CC individually.Pulled to V CC through a 10-kΩ resistor. When configuring multiple devices in the same JTAGchain, pull up each CONF_DONE pin to V CC individually. The CONF_DONE pin must have anexternal 10-kΩ pull-up resistor in order for the device to initialize.Driven high by connecting to V CC , pulling up through a resistor, or driving it high by somecontrol circuitry.Do not leave these pins floating. These pins support whichever non-JTAG configuration isused in production. If only JTAG configuration is used, you should tie these pins to ground.Do not leave these pins floating. Drive low or high, whichever is more convenient.Do not leave these pins floating. Drive low or high, whichever is more convenient.JTAG Configuration of Multiple DevicesWhen programming a JTAG device chain, one JTAG-compatible header,such as the ByteBlaster II header, is connected to several devices. Thenumber of devices in the JTAG chain is limited only by the drive capacityof the download cable. However, when four or more devices areconnected in a JTAG chain, Altera recommends buffering the TCK, TDI,and TMS pins with an on-board buffer.JTAG-chain device configuration is ideal when the system containsmultiple devices, or when testing your system using JTAG BST circuitry.Figure 13–20 shows multi-device JTAG configuration.Altera Corporation 13–35January 2007 Cyclone Device Handbook, Volume 1