From: Bdale Garbee Date: Tue, 27 Jul 2010 18:10:39 +0000 (-0600) Subject: more text moves X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=3233348ab772abdb48c1f176075ce7cc99e42875;p=web%2Faltusmetrum more text moves --- diff --git a/TeleMetrum/index.mdwn b/TeleMetrum/index.mdwn index d78b415..aea96d9 100644 --- a/TeleMetrum/index.mdwn +++ b/TeleMetrum/index.mdwn @@ -91,37 +91,6 @@ always want GPS on board, which lead to our current second generation boards. ## [Flight Logs](flightlogs) ## -## Problems ## - -* The CC1111F32 is a 36-pin QFN package, which necessitates reflow - soldering. Since we needed to reflow solder anyway, and because TI used - them in their reference design, we went a little crazy and used 0402 - passive parts everywhere. That means working under a microscope to - place parts! Without an inspection microscope, loading and testing these - boards might be impossible. - -* The addition of on-board GPS in v0.2 means that the total power consumption - can exceed the rate at which we draw power from the USB interface, - particularly when the GPS is in cold start mode. This means a battery must - be attached during operation, and also that the battery will only charge - effectively from USB when the board is turned off. - -* The v0.1 artwork had three issues, two of which required physical rework - on each board. All of these issues were fixed in v0.2. - - * The USB connector footprint was placed wrong, so that the - connector hung out over the edge of the board instead of being - flush. - * We needed chip select on the SPI memory. To fix that, we gave up the - ability to put the accelerometer into self-test mode and used that - GPIO line to pull chip select on the memory, which required two - cuts and two jumpers. - * The igniter sense circuits each needed a second resistor to - complete the voltage divider so our 3.3V CPU ADC could read the - 5V ejection voltage. This was fixed by changing two resistor - values, and tacking two additional resistors onto the board - with jumpers to ground. - ## Artifacts ## The user manual for TeleMetrum is available in @@ -168,6 +137,21 @@ Because we understand that not everyone uses Linux, development of a new cross-platform ground station program written in Java is underway for use with [AltOS](../AltOS). +## Problems ## + +* The CC1111F32 is a 36-pin QFN package, which necessitates reflow + soldering. Since we needed to reflow solder anyway, and because TI used + them in their reference design, we went a little crazy and used 0402 + passive parts everywhere. That means working under a microscope to + place parts! Without an inspection microscope, loading and testing these + boards might be impossible. + +* The addition of on-board GPS in v0.2 means that the total power consumption + can exceed the rate at which we draw power from the USB interface, + particularly when the GPS is in cold start mode. This means a battery must + be attached during operation, and also that the battery will only charge + effectively from USB when the board is turned off. + ## History ## ### v0.2 ### @@ -224,6 +208,22 @@ The differences between v0.1 and later boards were more substantial: The elimination of the discrete temperature sensor and second LED were necessary to support the companion board interface added in v0.2. +The v0.1 artwork had three issues, two of which required physical rework +on each board. All of these issues were fixed in v0.2. + +* The USB connector footprint was placed wrong, so that the + connector hung out over the edge of the board instead of being + flush. +* We needed chip select on the SPI memory. To fix that, we gave up the + ability to put the accelerometer into self-test mode and used that + GPIO line to pull chip select on the memory, which required two + cuts and two jumpers. +* The igniter sense circuits each needed a second resistor to + complete the voltage divider so our 3.3V CPU ADC could read the + 5V ejection voltage. This was fixed by changing two resistor + values, and tacking two additional resistors onto the board + with jumpers to ground. + The schematics and PCB artwork for this version as of the working-v0.1 tag are available here are pdf copies for easy reference: