diff --git a/6850.c b/6850.c
index f810d5f..b203ac2 100644
--- a/6850.c
+++ b/6850.c
@@ -6,7 +6,9 @@
 #include "6502.h"
 #include "6850.h"
 
-int n;
+static int n;
+static union UartStatusReg uart_SR;
+static uint8_t incoming_char;
 
 void init_uart() {
 	memory[DATA_ADDR] = 0;
diff --git a/6850.h b/6850.h
index 44f26c5..62c9459 100644
--- a/6850.h
+++ b/6850.h
@@ -19,10 +19,6 @@ union UartStatusReg {
 	uint8_t byte;
 };
 
-union UartStatusReg uart_SR;
-
-uint8_t incoming_char;
-
 void init_uart();
 
 void step_uart();