BBB cape construction - Githubissues

dfrister commented 9 years ago

@gstro @jmickiewicz Let me know which BBB GPIO pins will be routed to the DB9 connector.

gstro commented 9 years ago

We use 8 pins from port P9 (left column) numbers 1, 3, and 19-24

I2C

P9_19 - SCL
P9_20 - SDA
These lines are pulled up to VDD (3.3V) with resistors. I think our current values are 10kΩ and we're getting good responses from them, but they may change (prelim research shows 1k to 10k values are typical and we may want to drop to the lower side of the range with our higher capacitance). @jmickiewicz, please update on here if I'm missing something.

Daisy Chain

P9_21 - m_clk
P9_22 - m_do
P9_23 - select _(we are considering changing our flow from bottom-up to top-down. This line is currently to_above (mapping to from_below on the connected block) but could be considered to_below (mapping to from_above on the connected block). select should work)_

Global

P9_01 - GND
P9_03 - VDD
P9_24 - reset (If we can get a reset line from one of the unused DB9 pins that would be great. The reset lines are active LOW so a GPIO line that can sink current on pin 10 of the 461 (like the button already there) would allow the BBB to hard-reset all the blocks in the set at once, in addition to the what the buttons offer individually)

gstro commented 9 years ago

Update - changing to 3rd i2c-port, from PINs P9: 19 & 20 to 17 & 18 (i2c port not shown in graphic)

I2C

gstro commented 9 years ago

Hey @Debrant, can you give an update on the layout progress for cape 1 and cape 2 (#84)? Anything you need from us or can help with?

erebus-labs / blocks-o-code