VCCIO and EPCS Issue

[Altera_Forum]

Hi, All 

 We are using EPCS and CycloneIII device. As EPCS can only support 3.3V, the IO pin connect seems must Power by 3.3V, which means VCCIO of Bank1 in FPGA must tie to 3.3V power. Then here comes the question. Some AS Mode relative pin such as MSEL is in bank6, which used to configure the programme mode. Is this bank6 must power 3.3V VCCIO too?

[Altera_Forum]

No, Connect MSEL Pins to GND or 2.5V when using a Cyclone III Device. 

Also remember that the the JTAG and its pull ups are powered with 2.5V instead 3.3V. You can use the 2.5V voltage source you need to generate for VCCA Analog PLL power supply via LDO for example.

[Altera_Forum]

--- Quote Start ---  No, Connect MSEL Pins to GND or 2.5V when using a Cyclone III Device. Also remember that the the JTAG and its pull ups are powered with 2.5V instead 3.3V. You can use the 2.5V voltage source you need to generate for VCCA Analog PLL power supply via LDO for example.  --- Quote End ---     Why I need to connect MSEL pins to 2.5v if my JTAG is 3.3V?

[Altera_Forum]

Have a look at this Altera PDF 

configuration cyclone iii devices (http://www.altera.com/literature/hb/cyc3/cyc3_ciii51016.pdf) Page 50 Figure 9-24

[Altera_Forum]

--- Quote Start ---  No, Connect MSEL Pins to GND or 2.5V when using a Cyclone III Device. Also remember that the the JTAG and its pull ups are powered with 2.5V instead 3.3V. You can use the 2.5V voltage source you need to generate for VCCA Analog PLL power supply via LDO for example.  --- Quote End ---     One more question is MSEL is in bank6, do the VCCIO of bank6 need to be 2.5V, can I use it as 1.8V?

[Altera_Forum]

Page 11 of this PDF says : 

   --- Quote Start ---  Hardwire the MSEL pins to VCCA or GND without any pull-up or pull-down resistors to avoid any problems detecting an incorrect configuration scheme. Do not drive the MSEL pins with a microprocessor or another device.  --- Quote End ---    But if that means that this bank needs to be 2.5V too, i don't think so that MSEL interfears with Vio of a bank, but look into the pdf of your device.

[Altera_Forum]

The MSEL pins are completely independent. They are always used at 2.5V, and you can use any voltage you want for bank 6.

[Altera_Forum]

--- Quote Start ---  The MSEL pins are completely independent. They are always used at 2.5V, and you can use any voltage you want for bank 6.  --- Quote End ---   Great! Thanks