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how to test pins 28 & 29 — Parallax Forums

how to test pins 28 & 29

stargazer2050stargazer2050 Posts: 89
edited 2013-05-27 09:41 in Propeller 1
Quickstart bd
Oscilloscope

What to set up, what program might i run to check sda & scl
What should it look like (what to expect)
Can you run a blinking led program and see voltage jump up and down on those pins?

Comments

  • JonnyMacJonnyMac Posts: 9,107
    edited 2013-05-27 08:34
    If your Propeller can boot up ANY program after power up (i.e., not connected to a computer), pins 28 and 29 (the I2C pins to the boot EEPROM) are working.
  • stargazer2050stargazer2050 Posts: 89
    edited 2013-05-27 09:06
    Hi

    I f11'd an led flasher on pin zero and that boots fine.

    So why would i not be able to hook anything to 28 & 29 directly?

    Yesterday i posted "pca9554 io expander". In which i cant get that going.
    Also i can't put a compass on those pins yet it works ok on other io's
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-05-27 09:22
    stargazer2050, Are you aware that P28 and P29 are switched in order on the QuickStart?

    P29 (SDA) is on the left of P28 (SCL) (looking at the header from the front of the board).

    I've attached the QS's schematic.
    pdf
    pdf
    P8X32A QuickStart Rev A3 Schematic.pdf
    96K
  • stargazer2050stargazer2050 Posts: 89
    edited 2013-05-27 09:41
    Oh fer gosh sakes

    Thanks guys!
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