JSX - Revision history

Aoineko: /* Example */

2025-09-04T19:31:23Z

‎Example

Aoineko at 23:16, 10 February 2025

2025-02-10T23:16:34Z

Aoineko at 23:04, 10 February 2025

2025-02-10T23:04:21Z

Aoineko: /* No-communication state */

2024-10-23T07:45:42Z

‎No-communication state

Aoineko: /* Protocol */

2024-10-23T07:42:23Z

‎Protocol

Aoineko: /* States */

2024-10-23T07:41:43Z

‎States

Aoineko: /* Start communication and get ID */

2024-10-23T07:31:57Z

‎Start communication and get ID

Aoineko: /* Start communication and get ID */

2024-10-23T07:31:01Z

‎Start communication and get ID

Aoineko: /* Start communication and get ID */

2024-10-23T07:30:33Z

‎Start communication and get ID

Aoineko: /* No-communication state */

2024-10-21T12:01:08Z

‎No-communication state

@@ Line 89: / Line 89: @@
 == Example ==
-For a Joypad with a stick with X and Y axis (2 axis), and 4 buttons (1 row), the reading process would be:
+For a Joypad with 1 stick (2 axis, X and Y) and 4 buttons (1 row), the reading process would be:
 * After starting communication, first read to R#14 return the ID.<br/>ID: 0x09 [00 0010 01] for 2 axis, and 1 buttons row,
 * Next reading give X-axis value [0:63],

@@ Line 9: / Line 9: @@
 * then successive pulses on Pin 8 (LOW > HIGH) are used for data transmission (6 bits per 6 bits).
-Pin 6 and 7 are used as input only.
+Pin 7 is used as a data selector:
-Internal counter is used to send successive data: first the device ID, then each of the input data.
+Pin 6 is used as input only.
 Pin binding for received 6-bit data when reading through R#14:
@@ Line 30: / Line 34: @@
 Write R#15
-: Pin 8: LOW (for >1 ms)
+: Pin 8: HIGH (for >1 ms)
 : Reset internal data counter

@@ Line 1: / Line 1: @@
 == Protocol ==
-Proposal for a protocol to handle joypads with a variable number of sticks and buttons, plug in the MSX’s [https://www.msx.org/wiki/General_Purpose_port general purpose port].
+Proposal for a protocol to handle joypads with a '''variable number of sticks and buttons''', plug in the MSX’s '''[https://www.msx.org/wiki/General_Purpose_port general purpose port]'''.
-This protocol can manage joypads with up to 15 analog axis (one stick requires 2 axis) and 18 buttons.
+This protocol can manage joypads with up to '''15 analog axis''' (one stick requires 2 axis) and '''18 buttons''' (3 rows of 6 buttons each).
-A pulse on Pin 8 is used to start communication then (while Pin 8 still HIGH) consecutive pulse on Pin 6 is used to synchronize data transmission (6 bits per 6 bits).
+Pin 8 is used to synchronize data transmission:
-Pin binding for received data:
+Pin 6 and 7 are used as input only.
-<pre>
-Bits 7 6 5 4 3 2 1 0
+Internal counter is used to send successive data: first the device ID, then each of the input data.
-–-–-–-–-–-–-–-–--–-–-
-Pins x x 7 6 4 3 2 1
+Pin binding for received 6-bit data when reading through R#14:
-</pre>
+<syntaxhighlight>
 == States ==
-=== No-communication state ===
+=== Idle state (no-communication) ===
 Write R#15
-: Pin 8: LOW
+: Pin 8: LOW (for >1 ms)
-: Pin 6: ''any value''
+: Reset internal data counter
 Read R#14
@@ Line 25: / Line 37: @@
 : <u>Note</u>: It could be any value between 00-3F not already return by [https://www.msx.org/wiki/MSX-HID#List_of_known_fingerprints other MSX devices])
-=== Start communication and get ID ===
+=== Communication state ===
 Write R#15
-: Pin 8: LOW (in case Pin 8 have been modified by another device)
+: Pin 8: LOW
 Write R#15
-: Pin 8: HIGH (start communication)
+: Pin 8: HIGH (request data)
 Read R#14
-: Get JSX device ID
+: Get 6-bit data
-<pre>
-6 5 4 3 2 1 0
+Write R#15
-–-–-–-–-–-–-–-–--
+: Pin 8: LOW
- x x A A A A B B
+: Increment the internal counter
-     │ │ │ │ └─┴── Number of button rows (0-3)
-     └─┴─┴─┴────── Number of axis (0-15)
+==== Device ID ====
-</pre>
-:<u>Note</u>: Number of axis or number of button rows can be zero, but not both. So any device ID up to 0x3F is valid except 0x00.
+First available data is the JSX device ID:
-=== Read bytes ===
+Input number can be computed as:
-Repeat this step for each axis (if any), then for each button row (if any). Number of axis and button rows is given by the device ID
+* Axis number (<tt>Axies</tt>): <tt>ID >> 2</tt>,
-Write R#15
+Repeat data read, for each axis (if any), then for each button row (if any).
-: Pin 8: HIGH
+The device must be read <tt>TotIn</tt> times to read all data.
-Write R#15
+==== Axis data ====
-: Pin 8: HIGH
+Get 6-bit values
-: Pin 6: HIGH
+: unsigned 6-bits value [0:63]
-Read R#14
+==== Button row data ====
-: Get 6-bits values
+Get 6-bit values
-:: For axis:		signed 6-bits value [-32 ; 31]
+: bits field for 6 boutons (0: pressed, 1: released)
 == Example ==
 For a Joypad with a stick with X and Y axis (2 axis), and 4 buttons (1 row), the reading process would be:
 * After starting communication, first read to R#14 return the ID.<br/>ID: 0x09 [00 0010 01] for 2 axis, and 1 buttons row,
-* Next reading give X-axis value [-32 ; 31],
+* Next reading give X-axis value [0:63],
-* Next reading give Y-axis value [-32 ; 31],
+* Next reading give Y-axis value [0:63],
 * Next and last reading give button states (for up to 6 boutons).

@@ Line 23: / Line 23: @@
 Read R#14
 : Get 0x0F (JSX idle fingerprint)
-: (or any value between 00-3F not already return by [https://www.msx.org/wiki/MSX-HID#List_of_known_fingerprints other MSX devices])
+: <u>Note</u>: It could be any value between 00-3F not already return by [https://www.msx.org/wiki/MSX-HID#List_of_known_fingerprints other MSX devices])
 === Start communication and get ID ===

@@ Line 1: / Line 1: @@
 == Protocol ==
-Proposal for a protocol to handle a joypad with a variable number of sticks and buttons, plug in the MSX’s [https://www.msx.org/wiki/General_Purpose_port general purpose port].
+Proposal for a protocol to handle joypads with a variable number of sticks and buttons, plug in the MSX’s [https://www.msx.org/wiki/General_Purpose_port general purpose port].
 This protocol can manage joypads with up to 15 analog axis (one stick requires 2 axis) and 18 buttons.

@@ Line 44: / Line 44: @@
       └─┴─┴─┴────── Number of axis (0-15)
 </pre>
-:<u>Note</u>: Number of axis or number of buttons can be zero, but not both. So any device ID is valid except 0x00.
+:<u>Note</u>: Number of axis or number of button rows can be zero, but not both. So any device ID is valid except 0x00.
 === Read bytes ===

@@ Line 22: / Line 22: @@
 Read R#14
-: Get 0x0F (JSX fingerprint)
+: Get 0x0F (JSX idle fingerprint)
 : (or any value between 00-3F not already return by other MSX devices)