Keypads
Key maps
Each bit in the 900E0010-900E001F registers represents a key. If the bit is cleared, the key is being pressed. Only bits 0 to 10 are used in each halfword. The mapping depends on the currently used keypad.
Clickpad 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0010 | ret | enter | space | (-) | Z | . | Y | 0 | X | on | theta |
| 0012 | , | + | W | 3 | V | 2 | U | 1 | T | e^x | pi |
| 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 | click | C | home | B | menu | A | esc | | | tab | |
| 001E | up | u+r | right | r+d | down | d+l | left | l+u | 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0010 | down | left | right | up | |||||||
| 0012 | enter | + | - | * | / | ^ | clear | ||||
| 0014 | (-) | 3 | 6 | 9 | ) | tan | vars | ||||
| 0016 | . | 2 | 5 | 8 | ( | cos | prgm | stat | |||
| 0018 | 0 | 1 | 4 | 7 | , | sin | apps | X | |||
| 001A | on | sto | ln | log | x^2 | x^-1 | math | alpha | |||
| 001C | graph | trace | zoom | wind | y= | 2nd | mode | del | |||
| 001E |
Touchpad 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0010 | ret | enter | (-) | space | Z | Y | 0 | ?! | |||
| 0012 | X | W | V | 3 | U | T | S | 1 | pi | trig | 10^x |
| 0014 | R | Q | P | 6 | O | N | M | 4 | EE | x^2 | |
| 0016 | L | K | J | 9 | I | H | G | 7 | / | e^x | |
| 0018 | F | E | D | C | B | A | = | * | ^ | ||
| 001A | var | - | ) | . | ( | 5 | cat | frac | del | scratch | |
| 001C | flag | + | doc | 2 | menu | 8 | esc | tab | |||
| 001E | shift | ctrl | , |
Touchpad I²C
Communication with the actual touchpad is done with the I²C protocol: GPIO 1 is the Serial Clock (SCL) and GPIO 3 is the Serial Data Line (SDA). The touchpad responds to messages with address 0x20. A write message consists of the first port to write to, followed by the values to write: the port number auto-increments, so a message of 00 de ad writes de to port 00 and ad to port 01. A read message reads from whatever port was set by the previous write message, so it generally has to be preceded by an empty write to set the port.
A list of the touchpad's ports follows. All 16-bit numbers are big-endian.
- Any page:
- FF: Page number
- Page 04 (default):
- 00: Contact (usually is 01 if proximity >= 0x2F, 00 otherwise)
- 01: Proximity
- 02-03: X position
- 04-05: Y position
- 06: X velocity
- 07: Y velocity
- 0A: 1 if touchpad pressed down, 0 if not
- 0B: Status (reading this clears the low bits)
- Bit 0 (0x01): Set when proximity is nonzero
- Bit 1 (0x02): Set when velocity bytes are nonzero
- Bit 2 (0x04): Set when unknown byte at 08 is nonzero
- Bit 3 (0x08): Set when pressed byte has changed
- Bit 6 (0x40): Always set? (If it's not set, the OS's interrupt handler overflows the stack and crashes)
- E4-E7: Firmware version
- Page 10:
- 04-05: Maximum X coordinate (0x0918)
- 06-07: Maximum Y coordinate (0x069B)