commit 2a20d4

2026-03-21 15:03:23 Bob Green: -/-

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`programming/machine library.md` ..
@@ 6,3 6,20 @@
	```c
	#include <machine.h>
	```
+
+	## Serial I/O
+
+	## LED Control
+	There's a block of 10 leds (LD7 on the SBC3-b3), and six of them can be used for anything you like. Led1 is furthest from the cpu:
+	\| LED # \| Used for \|
+	\|:------\|:---------\|
+	\| 1 \| Indicates that the board is being powered via an external 5v supply. \|
+	\| 2 \| Indicated that the board is being powered via the ATX power connector. \|
+	\| 3 \| Connected to the ~RTS pin on the duart channel B. \|
+	\| 4 \| Connected to the ~RTS pin on the duart channel A. \|
+	\| 5 \| Available to user. \|
+	\| 6 \| Available to user. \|
+	\| 7 \| Available to user. \|
+	\| 8 \| Available to user. \|
+	\| 9 \| Available to user. \|
+	\| 10 \| Available to user. \|