pixo_replacement
Differences
This shows you the differences between two versions of the page.
| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| pixo_replacement [2023/03/10 17:39] – [Test Cases] millerjs | pixo_replacement [2024/11/14 02:30] (current) – external edit 127.0.0.1 | ||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ====== Raspberry Pi XO Replacement ====== | ====== Raspberry Pi XO Replacement ====== | ||
| + | Context: | ||
| * https:// | * https:// | ||
| + | |||
| + | ==== Success! ==== | ||
| + | Made an initial attempt on the evening of 2023-03-26 on a Pi 2 B. Drop in replacement is working surprisingly well right off. Have not performed any longitudinal testing yet, but initial tracking numbers are positive. | ||
| + | |||
| + | ^ Pi 2 B with replaced XO | ||
| + | | {{:: | ||
| ==== Notable Test Points ==== | ==== Notable Test Points ==== | ||
| Line 20: | Line 27: | ||
| * http:// | * http:// | ||
| + | |||
| + | As far as I can tell, the Pi 2B through 3B+ all use this part, as well as a number of the A models. The Pi 4B uses two AEL crystals, one at 25MHz, the other at 54MHz. I have not yet experimented with replacing these parts. | ||
| ==== New TCXO ==== | ==== New TCXO ==== | ||
| - | * [[https://media.digikey.com/ | + | * [[https://www.digikey.com/ |
| + | * [[https:// | ||
| - | ==== Test Cases ==== | ||
| - | Before I do this swap, I need to get a benchmark of (at least) two identical Pis so I have a baseline of their performance in stock configuration. These systems need to be as identical as possible, both in terms of software load out as well as their physical deployment. | ||
| - | === Software | + | ====== Quantifying Results ====== |
| - | * OS - Alpine Linux 3.17 | + | There are a number of different methods for quantifying the results of this sort of modification. A few that I am exploring will be detailed below. |
| - | * Timekeeping/measurement - chrony | + | ==== chrony tracking ===== |
| + | (Graphs coming eventually) | ||
| + | ==== Python Frequency Generator ==== | ||
| + | * [[https:// | ||
| + | * [[https:// | ||
| - | Configured to be as light and slim as possible. | + | <code python sigGen.py> |
| + | # | ||
| - | === Physical === | + | import RPi.GPIO as GPIO |
| + | from time import sleep | ||
| - | == Power == | + | GPIO.setmode(GPIO.BCM) |
| - | Meanwell 5v PSU powering both Pis. Either back-fed through | + | GPIO.setup(10, |
| + | p=GPIO.PWM(10, | ||
| + | p.start(20) | ||
| + | sleep(3600) | ||
| + | p.stop() | ||
| + | GPIO.cleanup() | ||
| + | exit() | ||
| + | </ | ||
| + | |||
| + | ==== WiringPi GPIO_CLOCK | ||
| + | The WiringPi toolset has a function to use the SoC's PLLs to generate a precise clock using the GPIO_CLOCK function. This can be initiated easily from the linux userspace by first setting | ||
| + | |||
| + | < | ||
| + | gpio mode 7 clock | ||
| + | gpio clock 7 1000000 # frequency in Hz | ||
| + | </ | ||
pixo_replacement.1678469991.txt.gz · Last modified: 2024/11/14 02:30 (external edit)