increased error checks for mcp23018_updat_matrix()

and some aesthetic stuff

doc/references.md

@@ -229,6 +229,9 @@
 
 ### Other
 
+* [Soarer's Converter (XT/AT/PS2/Terminal to USB Converter with NKRO)]
+  (http://geekhack.org/showwiki.php?title=Island:17458)
+
 * zip: [PJRC: blinky]
   (http://pjrc.com/teensy/blinky.zip)
 

src/keyboard/ergodox/layout.md

@@ -0,0 +1,18 @@
+# Documentation : layout
+
+## notes
+
+* Assuming 560 bytes for everything else in RAM space, there's 2000 bytes left
+  for the layout.  This should be enough for about 7 layers.  Watch your RAM
+  usage if you're getting close.
+
+  * The layout matricies could be moved to flash memory (program space, instead
+    of data space), but that doesn't seem necessary at the moment.  It would
+    also be slightly slower, though that probably shouldn't be a concern.
+
+-------------------------------------------------------------------------------
+
+Copyright &copy; 2012 Ben Blazak <benblazak.dev@gmail.com>  
+Released under The MIT License (MIT) (see "license.md")  
+Project located at <https://github.com/benblazak/ergodox-firmware>
+

src/keyboard/ergodox/mcp23018.c

@@ -60,7 +60,8 @@ uint8_t mcp23018_init(void) {
 	// - rows    : off : 0
 	// - columns : on  : 1
 	twi_start();
-	twi_send(TWI_ADDR_WRITE);
+	ret = twi_send(TWI_ADDR_WRITE);
+	if (ret) goto out;  // make sure we got an ACK
 	twi_send(GPPUA);
 	twi_send(0b11000000);  // GPPUA
 	twi_send(0b11111111);  // GPPUB
@@ -71,7 +72,8 @@ uint8_t mcp23018_init(void) {
 	// - rows    : high (hi-Z) : 1
 	// - columns : high (hi-Z) : 1
 	twi_start();
-	twi_send(TWI_ADDR_WRITE);
+	ret = twi_send(TWI_ADDR_WRITE);
+	if (ret) goto out;  // make sure we got an ACK
 	twi_send(OLATA);
 	twi_send(0b11111111);  //OLATA
 	twi_send(0b11111111);  //OLATB

src/lib/_teensy-2-0/twi.c

@@ -5,11 +5,12 @@
  *   (the code example in C), and section 20.8.1, figure 20-12
  * - Also see the documentation for `<util/twi.h>` at <http://www.nongnu.org/avr-libc/user-manual/group__util__twi.html#ga8d3aca0acc182f459a51797321728168>
  *
- * Some other (more complete) TWI libraries for the Teensy 2.0 (and other Amtel
+ * Some other (more complete) TWI libraries for the Teensy 2.0 (and other Atmel
  * processors):
  * - [i2cmaster] (http://homepage.hispeed.ch/peterfleury/i2cmaster.zip)
  *   - written by [peter-fleury] (http://homepage.hispeed.ch/peterfleury/)
- * - [the arduino twi library] (https://github.com/arduino/Arduino/tree/master/libraries/Wire/utility)
+ * - [the arduino twi library]
+ *   (https://github.com/arduino/Arduino/tree/master/libraries/Wire/utility)
  *   - look for an older version if you need one that doesn't depend on all the
  *     other Arduino stuff
  * ----------------------------------------------------------------------------

src/lib/pjrc/usb_keyboard/usb_keyboard.c

@@ -349,8 +349,8 @@ int8_t usb_keyboard_send(void)
 //
 ISR(USB_GEN_vect)
 {
-	uint8_t intbits, i;  // used to declare `t` as well, but it wasn't used
-	                     // ::Blazak, 2012::
+	uint8_t intbits, i;  // used to declare a variable `t` as well, but it
+			     //   wasn't used ::Blazak, 2012::
 	static uint8_t div4=0;
 
         intbits = UDINT;

src/lib/pjrc/usb_keyboard/usb_keyboard.h

@@ -19,7 +19,7 @@ extern volatile uint8_t keyboard_leds;
 #define usb_debug_flush_output()
 
 
-#if 0  // removed in favor of equilivent code elsewhere ::Ben Blazak, 2012::
+#if 0  // removed in favor of equivalent code elsewhere ::Ben Blazak, 2012::
 
 #define KEY_CTRL	0x01
 #define KEY_SHIFT	0x02

src/makefile

@@ -68,6 +68,7 @@ SIZE    = avr-size
 
 all: $(TARGET).hex $(TARGET).eep
 	@echo
+	@echo '---------------------------------------------------------------'
 	@echo '------- done --------------------------------------------------'
 	@echo
 	$(SIZE) --target=$(FORMAT) $(TARGET).hex
@@ -76,6 +77,9 @@ all: $(TARGET).hex $(TARGET).eep
 	@echo
 	@echo '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .'
 	@echo
+	$(SIZE) -C --mcu=atmega32u4 $(TARGET).elf
+	@echo '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .'
+	@echo
 	@echo 'you can load "$(TARGET).hex" and "$(TARGET).eep" onto the'
 	@echo 'Teensy using the Teensy loader'
 	@echo