From c5bc169461ce091eae529a1b6c6d12925ade6330 Mon Sep 17 00:00:00 2001
From: PlexSheep <software@cscherr.de>
Date: Sat, 9 Dec 2023 14:36:58 +0100
Subject: [PATCH] adc+rand

---
 include/adc.c  | 10 +++++-----
 include/rand.c |  2 ++
 print/main.c   |  3 ++-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/adc.c b/include/adc.c
index 0030d6e..0bba25d 100644
--- a/include/adc.c
+++ b/include/adc.c
@@ -10,9 +10,9 @@ void adc_init() {
 	ADMUX = (1<<REFS0);
 }
 uint16_t adc_read(uint8_t channel) {
-    ADMUX &= 0xf0;
-    ADMUX |= (channel & 0x0f);
-    ADCSRA |= (1<<ADSC);
-    while((ADCSRA&(1<<ADIF))==0);
-    return ADCL + (ADCH << 8);
+    ADMUX &= 0xf0; // max channel?
+    ADMUX |= (channel & 0x0f); // select channel
+    ADCSRA |= (1<<ADSC); // interrupt enable
+    while((ADCSRA&(1<<ADIF))==0); // wait for something
+    return ADCL + (ADCH << 8); // read
 }
diff --git a/include/rand.c b/include/rand.c
index a8159e5..6ca6004 100644
--- a/include/rand.c
+++ b/include/rand.c
@@ -1,5 +1,7 @@
+#include "adc.h"
 int rand() {
     static unsigned int seed = 1337191337;
+    seed *= adc_read(3);
     unsigned int buf[] = {
         (seed*31832)%677,
         (seed*32932)%2332
diff --git a/print/main.c b/print/main.c
index 3bd2214..f25527b 100644
--- a/print/main.c
+++ b/print/main.c
@@ -17,7 +17,6 @@ int main (void)
     adc_init();
     sei();
 
-    char buf[10];
     uint16_t sensor[2] = { 0, 1 };
 
     while (1)
@@ -28,6 +27,8 @@ int main (void)
         // we want to print this, so we store the ascii repr in our buffer
         uart_printi("sensor 0: ", sensor[0]);
         uart_printi("sensor 1: ", sensor[1]);
+        uart_printi("sensor 2 (noise): ", adc_read(2));
+        uart_printi("rand: ", rand());
         _delay_ms(1000);
     }
 }