3.3v for SB6121

SB6XXX,SBV6XXX

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usbbdm
Posts: 8495
Joined: Mon Jul 18, 2005 9:33 pm

3.3v for SB6121

Post by usbbdm » Sat Dec 28, 2019 11:41 pm

I have a user constantly talk to me over the chat that he cannot program SB6121.
In my youtube video https://www.youtube.com/watch?v=pFoXLnORZyY&t=9s I used a hack from USB JTAG NT to get 3.3v. Actually the 3.3v from USB JTAG NT is a little higher and not very reliable.
In his setup he used 3.3v from TTL and never worked for him.
Today I measured the power and found it drain about 450mA from the TTL and failed. The power supply also drops to 2.8XV.
So in this kind of setup, you should get a good source of 3.3v that can provide 750mA or bigger to get reliable programming.
The USB powered device can provide 500mA max include USB JTAG NT itself.
Make yourself a good 3.3v source is the key to get this kind of setup working.
If you program the chip off the board , then TTL 3.3v should be sufficient. When programming on the board, you are not only powering the SPI flash, you are also powering other devices on the board.