Difference between revisions of "83Plus:Ports:01"
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| − | + | == Synopsis == | |
| − | + | '''Port Number:''' 01h | |
| − | + | '''Function:''' Keyboard Port | |
| + | |||
| + | This port controls the on-calc keypad. The keypad is divided into a series of groups. | ||
| + | |||
| + | === Read Values === | ||
| + | * Bits are set according whether corresponding keys from selected groups are pressed. Groups are selected through writing to the port. A pressed key reads a 0 bit. An unpressed key reads a 1 bit. The port reads FF after a reset (write FF). | ||
| + | |||
| + | === Write Values === | ||
| + | * $FF : Reset the keypad. This unselects all groups and resets the keypad state. | ||
| + | * Anything else : Any 0 bit adds the corresponding group to the list of monitored groups. When a key in a monitored group is pressed, the corresponding key bit reads 1. | ||
| + | |||
| + | == Comments == | ||
| + | The key map is laid out as follows: | ||
| + | |||
| + | <nowiki> Group Bit -> 0 1 2 3 4 5 6 7 | ||
| + | Group Mask -> FE FD FB F7 EF DF BF 7F | ||
| + | Key Bit (Mask) | ||
| + | 0 (FE) | DOWN|ENTER| (-) | . | 0 | |GRAPH| | | ||
| + | 1 (FD) | LEFT| + | 3 | 2 | 1 | STO |TRACE| | | ||
| + | 2 (FB) |RIGHT| - | 6 | 5 | 4 | LN |ZOOM | | | ||
| + | 3 (F7) | UP | * | 9 | 8 | 7 | LOG |WIND | | | ||
| + | 4 (EF) | | / | ) | ( | , | x^2 | Y= | | | ||
| + | 5 (DF) | | ^ | TAN | COS | SIN |x^-1 | 2nd | | | ||
| + | 6 (BF) | |CLEAR|VARS |PRGM |APPS |MATH |MODE | | | ||
| + | 7 (7F) | | | |STAT |X,T..|ALPHA| DEL | | | ||
| + | |||
| + | NOTE: Group FB Key FE is NEGATE, not to be confused SUBTRACT. | ||
| + | NOTE: Group DF Key FE could be ON, but the ON key is tested elsewhere (a "special case" key - after all, it is the ON key). | ||
| + | |||
| + | == Example == | ||
| + | <nowiki>ld a, 0FFh ;Reset the keypad. | ||
| + | out (1), a | ||
| + | ld a, 0FEh ;Select group 0. | ||
| + | out (1), a | ||
| + | in a, (1) ;Test for keys. | ||
| + | and 0FDh ;Test for Left Arrow key. Basically set all other bits to 0. This means A becomes 0 if left was pressed. | ||
| + | call z, LeftArrowPressed ;If A==0 then Left Arrow bit was reset, meaning it was pressed. | ||
| + | ld a, 0FFh ;Reset the keypad. | ||
| + | out (1), a</nowiki> | ||
| + | |||
| + | == Credits and Contributions == | ||
| + | * '''/dev/console:''' For letting me type all this. | ||
Revision as of 21:52, 26 March 2005
Synopsis
Port Number: 01h
Function: Keyboard Port
This port controls the on-calc keypad. The keypad is divided into a series of groups.
Read Values
- Bits are set according whether corresponding keys from selected groups are pressed. Groups are selected through writing to the port. A pressed key reads a 0 bit. An unpressed key reads a 1 bit. The port reads FF after a reset (write FF).
Write Values
- $FF : Reset the keypad. This unselects all groups and resets the keypad state.
- Anything else : Any 0 bit adds the corresponding group to the list of monitored groups. When a key in a monitored group is pressed, the corresponding key bit reads 1.
Comments
The key map is laid out as follows:
Group Bit -> 0 1 2 3 4 5 6 7
Group Mask -> FE FD FB F7 EF DF BF 7F
Key Bit (Mask)
0 (FE) | DOWN|ENTER| (-) | . | 0 | |GRAPH| |
1 (FD) | LEFT| + | 3 | 2 | 1 | STO |TRACE| |
2 (FB) |RIGHT| - | 6 | 5 | 4 | LN |ZOOM | |
3 (F7) | UP | * | 9 | 8 | 7 | LOG |WIND | |
4 (EF) | | / | ) | ( | , | x^2 | Y= | |
5 (DF) | | ^ | TAN | COS | SIN |x^-1 | 2nd | |
6 (BF) | |CLEAR|VARS |PRGM |APPS |MATH |MODE | |
7 (7F) | | | |STAT |X,T..|ALPHA| DEL | |
NOTE: Group FB Key FE is NEGATE, not to be confused SUBTRACT.
NOTE: Group DF Key FE could be ON, but the ON key is tested elsewhere (a "special case" key - after all, it is the ON key).
== Example ==
<nowiki>ld a, 0FFh ;Reset the keypad.
out (1), a
ld a, 0FEh ;Select group 0.
out (1), a
in a, (1) ;Test for keys.
and 0FDh ;Test for Left Arrow key. Basically set all other bits to 0. This means A becomes 0 if left was pressed.
call z, LeftArrowPressed ;If A==0 then Left Arrow bit was reset, meaning it was pressed.
ld a, 0FFh ;Reset the keypad.
out (1), a
Credits and Contributions
- /dev/console: For letting me type all this.
