SX Key rev. E problems

william chan

I have had about 8 pcs SX28DP and 3 pcs of SX18AC75/DP "killed" by SXKey rev. E in the past 1 month alone.
The SXKey Rev E is still workable and can program chips, but it is more likely to get downloading errors than the SXKey rev F.

When the chips die for no apparent reason, the will not run (oscillate ) and will not allow itself to be programmed again.

At first I thought the 4 hole header socket on the SXKey rev E could be "loose", so I changed the socket. No Effect.
The downloading errors still occur much more often than SXKey rev F.

The sequence of tries is like this.

1. Disconnect power
2. Connect back power
3. Try to download, if fails, go back to 1.

For SXKey rev E usually takes 3 to 6 tries before successful.
For SXKey rev F only 1 or 2 tries.

I am afraid to use the SXKey rev. E anymore.

My questions :-

1. Could there be compatibility problems between SXKey RevE and the latest v3.1 IDE?
Is anybody still using SX-Key rev E?

2. If during downloading into the SX chip, the connection to the 4 pin header is suddenly lost, can it in any way cause the SX Chip to be in a "limbo state" that can no longer accept new downloads?

3. Why the SXKey rev E seems to have a only 2 wire coaxial cable to the PC serial port?
I would think that at least 3 wires are needed for 2 way communications.

4. How to ressurrect an SX chip "killed" by downloading inconsistencies?

Jon Williams

You might want to check your connections -- I go back-and-forth between Rev E and Rev F keys all the time an never have any problems. I'm usually programming my SX28 on a PDB which has good connections and a very stout power supply.

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Jon Williams
Applications Engineer, Parallax