diff --git a/2ano/2semestre/ac2/aula04/part1-2.c b/2ano/2semestre/ac2/aula04/part1-2.c
index d0adb19..c8b8eab 100644
--- a/2ano/2semestre/ac2/aula04/part1-2.c
+++ b/2ano/2semestre/ac2/aula04/part1-2.c
@@ -7,16 +7,14 @@ void delay(int ms) {
 
 int main() {
     // Configure RE6-RE3 as output
-    TRISE = TRISE & 0xFF87;
+    TRISE &= 0xFF87;
     // Initialize the counter
     unsigned int counter = 0;
     
     while (1) {
-        // Update value
-        LATE = (LATE & 0xFF87) // Reset bits 6-3
-               | counter << 3; // Merge with counter
+        LATE = (LATE & 0xFF87) | counter++ << 3;
+        counter %= 10;
         
         delay(460);
-        counter = (counter + 1) % 10;
     }
 }
diff --git a/2ano/2semestre/ac2/aula04/part1-3.c b/2ano/2semestre/ac2/aula04/part1-3.c
index 983f017..f1154e8 100644
--- a/2ano/2semestre/ac2/aula04/part1-3.c
+++ b/2ano/2semestre/ac2/aula04/part1-3.c
@@ -7,16 +7,14 @@ void delay(int ms) {
 
 int main() {
     // Configure RE6-RE3 as output
-    TRISE = TRISE & 0xFF87;
+    TRISE &= 0xFF87;
     // Initialize the counter
     unsigned int counter = 0;
     
     while (1) {
-        // Update value
-        LATE = (LATE & 0xFF87) // Reset bits 6-3
-               | counter << 3; // Merge with counter
+        LATE = (LATE & 0xFF87) | counter << 3;
+        counter = (counter + 9) % 10;
         
         delay(370);
-        counter = (counter + 9) % 10;
     }
 }
diff --git a/2ano/2semestre/ac2/aula04/part2-1.c b/2ano/2semestre/ac2/aula04/part2-1.c
new file mode 100644
index 0000000..f63e103
--- /dev/null
+++ b/2ano/2semestre/ac2/aula04/part2-1.c
@@ -0,0 +1,14 @@
+#include <detpic32.h>
+
+int main() {
+    // Configure ports as output
+    TRISB &= 0x80FF; // Use bits 14-8
+    TRISD &= 0xFF9F; // Use bits 6-5
+
+    // Select only least significative display
+    LATD = (LATD & 0xFF9F) | 0x0020;
+
+    while (1) LATB = LATB & 0x80FF | 0x0100 << (getChar() - 'a');
+
+    return 0;
+}
diff --git a/2ano/2semestre/ac2/aula04/part2-2.c b/2ano/2semestre/ac2/aula04/part2-2.c
new file mode 100644
index 0000000..f3bbee3
--- /dev/null
+++ b/2ano/2semestre/ac2/aula04/part2-2.c
@@ -0,0 +1,26 @@
+#include <detpic32.h>
+
+void delay(unsigned int ms) {
+    resetCoreTimer();
+    while(readCoreTimer() < 20000 * ms);
+}
+
+int main() {
+    // Configure ports as output
+    TRISB &= 0x80FF; // Use bits 14-8
+    TRISD &= 0xFF9F; // Use bits 6-5
+
+    // Select least significative display
+    LATD = (LATD & 0xFF9F) | 0x0020;
+
+    while (1) {
+        unsigned char segment = 1;
+        for (; segment < (1<<7); segment <<= 1) {
+            LATB = (LATB & 0x80FF) | segment << 8;
+            delay(500);
+        }
+        LATD ^= 0x0060;
+    }
+
+    return 0;
+}
diff --git a/2ano/2semestre/ac2/aula04/part2-5.c b/2ano/2semestre/ac2/aula04/part2-5.c
new file mode 100644
index 0000000..0b9583e
--- /dev/null
+++ b/2ano/2semestre/ac2/aula04/part2-5.c
@@ -0,0 +1,25 @@
+#include <detpic32.h>
+
+const unsigned int dis7Scodes[] = {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D,
+                                   0xFD, 0x07, 0x7F, 0x6F, 0x77, 0xFC,
+                                   0x39, 0x5E, 0xF9, 0xF1};
+
+void delay(unsigned int ms) {
+    resetCoreTimer();
+    while (readCoreTimer() < 20000 * ms);
+}
+
+int main() {
+    TRISB &= 0x80FF;
+    TRISD &= 0xFF9F;
+    LATD = (LATD & 0xFF9F) | 0x0020;
+
+    unsigned int n = 0;
+    while (1) {
+        LATB = (LATB & 0x80FF) | dis7Scodes[n++] << 8;
+        n %= 16;
+        delay(500);
+    }
+
+    return 0;
+}