I was recently working a project that was based on Parallax's industrial Stamp Controller Interface Board and the BASIC Stamp 2. We needed to upgrade the system to use the more robust BS2e microcontroller and were told by Parallax support that this was no problem. We received the new parts and began testing the setup only to find that the line drivers where not supplying enough voltage on logic high (only 1.5v) to trigger the BS2e's input pins (when it had worked fine with the BS2). After talking numerous times with Parallax support we came to the conclusion that there needed to be a pull-up resistor soldered to the boards prototype area. A 5.6k-Ohm resistor between each input pin and +5v seemed to do the trick. While this worked, I was not very happy with the solution. The problem stems from the fact that the BS2 is based on the PIC microcontroller and the BS2e on Ubicom's SX chip. When I asked if they where going to update the board design to resolve this issue, tech support said that they where not because the person who originally designed the board is no longer at Parallax.
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