Found a wiring for the buttons that works.

README.md

@@ -14,11 +14,10 @@ is the result.
 # COMPILING
 Please have a look at the sourcecode. It is imperative that the GPIO numbering from the 
 (deprecated) sysfs is being reflected in the physicalmapping[] array. Thus, the first time you 
-try to compile it, it will fail. 
+try to compile it, it will fail. You need to configure lines 21-26. I am really really sorry.
-Find the #if 0 line which reflects your board, or find the correct sysfs mapping for your board.
+(Yes, both files. oledtest.c as well as keytest.c)
-Really really sorry, this is what happens when you become a maker.
 
-Once you changed one of the #if 0 to #if 1, you can compile it with
+Once you have done this, please run
 
 gcc -O3 -o oledtest.app oledtest.c
 gcc -O3 -o keytest.app keytest.c

keytest.c

@@ -17,6 +17,15 @@ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+
+// Configuration starts here
+//#define PATCHED_WIRING		// comment in if you did the EXACT SAME wiring as I did ;)
+//#define PINOUT_JETSONNANO		// comment in if you connected the SH1106 directly to a Jetson Nano
+//#define PINOUT_BANANAPI		// comment in if you connected the SH1106 directly to a Banana Pi Zero
+//#define PINOUT_RASPBERRYPI		// comment in if you connected the SH1106 directly to a Raspberry Pi (Zero)
+// Configuration ends here
+
+
 #include <stdlib.h>
 #include <signal.h>
 #include <stdio.h>
@@ -47,40 +56,39 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define	BITMAP_HEIGHT	64
 #define	BITMAP_WIDTH	128
 
-
 //// depends on the development board
 
 // the way I understand this is, that the physical pins are mapped into
 // the system memory. to accces those, there is some sort of memory
 // offset maybe
-#if 0
+#if defined(PINOUT_JETSONNANO)
 #warning "This mapping is for the Jetson Nano board."
 // Jetson Nano
 // source: https://maker.pro/nvidia-jetson/tutorial/how-to-use-gpio-pins-on-jetson-nano-developer-kit
 const short physicalmapping[41]={
 	0,	// placeholder. there is no PIN0
 	 -1, -1,// PIN1 =3.3V DC, PIN2 =5V DC
-	 -1, -1,
+	 -1, -1,// 3,4
-	 -1, -1,
+	 -1, -1,// 5,6
 	216, -1, //PIN7 = AUDIO_MCLK
-	 -1, -1,
+	 -1, -1, //9,10
 	 50, 79, //PIN11=UART_2_RTS,PIN12=I2S_4_CLK
-	 14, -1, 
+	 14, -1, //13,14
-	194,232,
+	194,232, //15,16
-	 -1, 15,
+	 -1, 15, //17,18
-	 16, -1,
+	 16, -1, //19,20
-	 17, 13,
+	 17, 13, //21,22
-	 18, 19,
+	 18, 19, //23,24
-	 -1, 20,
+	 -1, 20, //25,26
-	 -1, -1,
+	 -1, -1, //27,28
-	149, -1,
+	149, -1, //29,30
-	200,168,
+	200,168, //31,32
-	 38, -1,
+	 38, -1, //33,34
-	 76, 51,
+	 76, 51, //35,36
-	 12, 77,
+	 12, 77, //37,38
-	 -1, 78
+	 -1, 78  //39,40
 };
-#elif 0
+#elif defined(PINOUT_BANANAPI)
 #warning "This mapping is for the Banana Pi board."
 // source: https://wiki.fw-web.de/doku.php?id=en:bpi-r64:gpio
 const short physicalmapping[41]={
@@ -106,8 +114,8 @@ const short physicalmapping[41]={
 	 86, -1, //37,38
 	 -1, -1  //39,40
 };
-#elif 1
+#elif defined(PINOUT_RASPBERRYPI) 
-#warning "This mapping is for the Raspberry Pi Zero W 1.1 board"
+#warning "This mapping is for the Raspberry Pi (Zero) board"
 // source: https://www.theengineeringprojects.com/wp-content/uploads/2021/03/raspberry-pi-zero-5.png
 // NOTE: GPIO16 was actually missing in the diagram.
 const short physicalmapping[41]={
@@ -134,11 +142,36 @@ const short physicalmapping[41]={
 	 -1, 21  //39,40
 };
 #else
-#error "Please have a look at the source code and select one of the mappings from the sysfs numbering to the physical pins"
+#error "The physical pins need to be mapped to the GPIO numbers. For some reason, those numbers are different for each board out there. So please have a look at the sourcecode, lines 21-26, and select the one that works best for you."
+const int physicalmapping[41]={0};
 #endif
 
 // this is the GPIO pinout for the waveshare OLED 1.3 SH1106 hat
 // source: https://www.waveshare.com/1.3inch-oled-hat.htm
+
+#ifdef	PATCHED_WIRING
+// Apparently, not every Key was mapped to a working GPIO pin. 
+// So I did some rewiring. This is a setup that works
+#define	PIN_LEFT	(physicalmapping[ 3])	// OLED pin 29
+#define	PIN_UP		(physicalmapping[ 5])	// OLED pin 31
+#define	PIN_FIRE	(physicalmapping[ 7])	// OLED pin 33
+#define	PIN_DOWN	(physicalmapping[29])	// OLED pin 35
+#define	PIN_RIGHT	(physicalmapping[31])	// OLED pin 37
+
+#define	PIN_KEY1	(physicalmapping[27])	// OLED pin 36
+#define	PIN_KEY2	(physicalmapping[24])	// OLED pin 38
+#define	PIN_KEY3	(physicalmapping[26])	// OLED pin 40
+
+#define	PIN_BL		(physicalmapping[16])	// OLED pin 12
+#define	PIN_DC		(physicalmapping[18])
+#define	PIN_RST		(physicalmapping[22])
+#define PIN_CS		(physicalmapping[28])	// OLED pin 24
+
+#define	PIN_MOSI	(physicalmapping[19])
+#define	PIN_MISO	(physicalmapping[21])
+#define	PIN_SCLK	(physicalmapping[23])
+
+#else
 #define	PIN_LEFT	(physicalmapping[29])
 #define	PIN_UP		(physicalmapping[31])
 #define	PIN_FIRE	(physicalmapping[33])
@@ -149,14 +182,17 @@ const short physicalmapping[41]={
 #define	PIN_KEY2	(physicalmapping[38])
 #define	PIN_KEY3	(physicalmapping[40])
 
-#define	PIN_BL	(physicalmapping[12])
+#define	PIN_BL		(physicalmapping[12])
-#define	PIN_DC	(physicalmapping[18])
+#define	PIN_DC		(physicalmapping[18])
-#define	PIN_RST	(physicalmapping[22])
+#define	PIN_RST		(physicalmapping[22])
-#define PIN_CS	(physicalmapping[24])
+#define PIN_CS		(physicalmapping[24])
 
 #define	PIN_MOSI	(physicalmapping[19])
 #define	PIN_MISO	(physicalmapping[21])
 #define	PIN_SCLK	(physicalmapping[23])
+#endif
+
+
 
 
 int gpio_export(int pin)

oledtest.c

@@ -17,6 +17,15 @@ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
+
+// Configuration starts here
+//#define PATCHED_WIRING		// comment in if you did the EXACT SAME wiring as I did ;)
+//#define PINOUT_JETSONNANO		// comment in if you connected the SH1106 directly to a Jetson Nano
+//#define PINOUT_BANANAPI		// comment in if you connected the SH1106 directly to a Banana Pi Zero
+//#define PINOUT_RASPBERRYPI		// comment in if you connected the SH1106 directly to a Raspberry Pi (Zero)
+// Configuration ends here
+
+
 #include <stdlib.h>
 #include <signal.h>
 #include <stdio.h>
@@ -53,7 +62,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // the way I understand this is, that the physical pins are mapped into
 // the system memory. to accces those, there is some sort of memory
 // offset maybe
-#if 0
+#if defined(PINOUT_JETSONNANO)
 #warning "This mapping is for the Jetson Nano board."
 // Jetson Nano
 // source: https://maker.pro/nvidia-jetson/tutorial/how-to-use-gpio-pins-on-jetson-nano-developer-kit
@@ -80,7 +89,7 @@ const short physicalmapping[41]={
 	 12, 77, //37,38
 	 -1, 78  //39,40
 };
-#elif 0
+#elif defined(PINOUT_BANANAPI)
 #warning "This mapping is for the Banana Pi board."
 // source: https://wiki.fw-web.de/doku.php?id=en:bpi-r64:gpio
 const short physicalmapping[41]={
@@ -106,8 +115,8 @@ const short physicalmapping[41]={
 	 86, -1, //37,38
 	 -1, -1  //39,40
 };
-#elif 0
+#elif defined(PINOUT_RASPBERRYPI) 
-#warning "This mapping is for the Raspberry Pi Zero W 1.1 board"
+#warning "This mapping is for the Raspberry Pi (Zero) board"
 // source: https://www.theengineeringprojects.com/wp-content/uploads/2021/03/raspberry-pi-zero-5.png
 // NOTE: GPIO16 was actually missing in the diagram.
 const short physicalmapping[41]={
@@ -134,11 +143,36 @@ const short physicalmapping[41]={
 	 -1, 21  //39,40
 };
 #else
-#error "Please have a look at the source code and select one of the mappings from the sysfs numbering to the physical pins"
+#error "The physical pins need to be mapped to the GPIO numbers. For some reason, those numbers are different for each board out there. So please have a look at the sourcecode, lines 21-26, and select the one that works best for you."
+const int physicalmapping[41]={0};
 #endif
 
 // this is the GPIO pinout for the waveshare OLED 1.3 SH1106 hat
 // source: https://www.waveshare.com/1.3inch-oled-hat.htm
+
+#ifdef	PATCHED_WIRING
+// Apparently, not every Key was mapped to a working GPIO pin. 
+// So I did some rewiring. This is a setup that works
+#define	PIN_LEFT	(physicalmapping[ 3])	// OLED pin 29
+#define	PIN_UP		(physicalmapping[ 5])	// OLED pin 31
+#define	PIN_FIRE	(physicalmapping[ 7])	// OLED pin 33
+#define	PIN_DOWN	(physicalmapping[29])	// OLED pin 35
+#define	PIN_RIGHT	(physicalmapping[31])	// OLED pin 37
+
+#define	PIN_KEY1	(physicalmapping[27])	// OLED pin 36
+#define	PIN_KEY2	(physicalmapping[24])	// OLED pin 38
+#define	PIN_KEY3	(physicalmapping[26])	// OLED pin 40
+
+#define	PIN_BL		(physicalmapping[16])	// OLED pin 12
+#define	PIN_DC		(physicalmapping[18])
+#define	PIN_RST		(physicalmapping[22])
+#define PIN_CS		(physicalmapping[28])	// OLED pin 24
+
+#define	PIN_MOSI	(physicalmapping[19])
+#define	PIN_MISO	(physicalmapping[21])
+#define	PIN_SCLK	(physicalmapping[23])
+
+#else
 #define	PIN_LEFT	(physicalmapping[29])
 #define	PIN_UP		(physicalmapping[31])
 #define	PIN_FIRE	(physicalmapping[33])
@@ -149,14 +183,15 @@ const short physicalmapping[41]={
 #define	PIN_KEY2	(physicalmapping[38])
 #define	PIN_KEY3	(physicalmapping[40])
 
-#define	PIN_BL	(physicalmapping[12])
+#define	PIN_BL		(physicalmapping[12])
-#define	PIN_DC	(physicalmapping[18])
+#define	PIN_DC		(physicalmapping[18])
-#define	PIN_RST	(physicalmapping[22])
+#define	PIN_RST		(physicalmapping[22])
-#define PIN_CS	(physicalmapping[24])
+#define PIN_CS		(physicalmapping[24])
 
 #define	PIN_MOSI	(physicalmapping[19])
 #define	PIN_MISO	(physicalmapping[21])
 #define	PIN_SCLK	(physicalmapping[23])
+#endif