Memory-mapped I/O ports

0x900E0010-0x900E001F - Keypad

(Read?)-Write, half-word (only?)

Keypad map. Each bit represents a key. If bit is cleared, the key is being pressed. Only bit 0 to 11 are used. The mapping depends on the currently used keypad (TI-Nspire or TI-84+).

TI-Nspire keypad map:

offset	bit 0	bit 1	bit 2	bit 3	bit 4	bit 5	bit 6	bit 7	bit 8	bit 9	bit 10	bit 11
0010	ret	enter	space	(-)	Z	.	Y	0	X	---	theta	on
0012	,	+	W	3	V	2	U	1	T	e^x	pi	click
0014	?	-	S	6	R	5	Q	4	P	10^x	EE	---
0016	:	*	O	9	N	8	M	7	L	x^2	i	---
0018	"	/	K	tan	J	cos	I	sin	H	^	>	---
001A	'	cat	G	)	F	(	E	var	D	caps	<	---
001C	flag	---	C	home	B	menu	A	esc	|	tab	=	---
001E	up	---	right	---	down	---	left	---	clear	ctrl	=	---

TI-84+ keypad map:

offset	bit 0	bit 1	bit 2	bit 3	bit 4	bit 5	bit 6	bit 7	bit 8	bit 9	bit 10
down	left	right	up	---	---	---	---	---	---	---	on
enter	+	-	*	/	^	clear	---	---	---	---	---
(-)	3	6	9	)	tan	vars	---	---	---	---	---
.	2	5	8	(	cos	prgm	stat	---	---	---	---
0	1	4	7	,	sin	apps	X	---	---	---	---
---	sto	ln	log	x^2	x^-1	math	alpha	---	---	---	---
graph	trace	zoom	wind	y=	2nd	mode	del	---	---	---	---
---	---	---	---	---	---	---	---	---	---	---	---

A4000100-A40096FF - Screen

Read-write, byte, half-word, word

Screen buffer. The upper left corner is the first byte. Each grayscaled pixel is 4-bit long. 1111 is white, 0000 is black.