From b10690f16d2b310221ffa7995e779f09d146f7f8 Mon Sep 17 00:00:00 2001 From: Sadeep Madurange Date: Mon, 5 Jan 2026 13:52:16 +0800 Subject: Tighten etlas prose. --- _site/log/etlas/index.html | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) (limited to '_site/log/etlas') diff --git a/_site/log/etlas/index.html b/_site/log/etlas/index.html index 9362917..f618503 100644 --- a/_site/log/etlas/index.html +++ b/_site/log/etlas/index.html @@ -54,20 +54,18 @@ DHT22 sensor.

-

Stocks: Two weeks EOD prices from Polygon.io (max SRAM holds). Flask app on VPS -relays feed, lets me swap symbols via config. FastCGI + httpd + htpasswd.

+

Stocks: Two weeks EOD prices from Polygon.io (max possible). Flask app on VPS +relays feed; manages watchlist. Backend: httpd + htpasswd + FastCGI + Flask.

-

gui_plot_stocks() triggers WDT. vTaskDelay() prevents that. Stepped graph was -easier to code for the bit-packed framebuffer (not enough memory for much -else), but it’s messy–too messy.

- -

Note to self: Refactor gui_plot_stocks(). Bresenham’s line algorithm perhaps?

+

gui_plot_stocks() triggers watchdog; vTaskDelay() required. Stepped graph was +easier to implement (under memory constraints), but the logic is hideous. Note +to self: Refactor with Bresenham’s?

News: Channel NewsAsia RSS. MCU parses XML directly. Character glyphs stored as -bitmaps in sprites directory.

+bitmaps in header files.

-

Weather: DHT22 via PWM. 26µs/50µs/70µs pulses too fast for standard ESP32 APIs. -Compare relative pulse widths:

+

Weather: DHT22 single-wire protocol. 26µs/50µs/70µs pulses are too fast for +standard ESP32 APIs. Bit-banged relative pulse widths: (Ported from ESP8266):

static inline int dht_await_pin_state(int state, int timeout)
 {
@@ -124,14 +122,12 @@ static inline int dht_get_raw_data(unsigned char buf[BUFLEN])
 }
-

Ported from ESP8266.

- -

After flashing new versions, display would stop responding. Didn’t observe this -with e-reader. Issue occurs spontaneously. Couldn’t find root cause. Making a -change like adding a comment or tweaking delay in refresh() (then changing -back) fixed it. Noisy electrical connections?

+

Ghost in the machine: epd_init() stalls intermittently on first refresh() after +flash. Toggling delay values in refresh() resolves it. If first refresh +succeeds, it remains stable. Root cause unknown–suspected power supply issues +from powering display via MCU.

-

Once running, it runs: August 2024 - December 2025.

+

Uptime: August 2024 - January 2026

Commit: a92c86a

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