These pages wos and timex.comboios.info suggest the fire button of the Timex TC/TS 2068 joystick is read at bit 4.
Input:
bit D0: up (0=active) bit D1: down bit D2: left bit D3: right bit D4: fire (0=active) bits D5-D7: last values sent to these bits
However looking at the schematics of the TS 2068 technical manual, it seems to be bit 7.
Am I wrong?
Androids Timex cartridge game disassembled machine code using bit 7, for checking the Timex joystick 1 0x1F6 port for the fire button:
ld a,00eh out (0f5h),a ld a,001h in a,(0f6h) bit 7,a <------- ret nz Pinball Timex cartridge game disassembled machine code using bit 7, for checking the Timex joystick 1 0x1F6 port for the fire button:
ld a,00eh out (0f5h),a ld a,001h in a,(0f6h) bit 7,a <------- jr z,$+15 Bit 7 surely is not an "unused" bit, it is the button/fire.
Interestingly enough, this also means the Timex 2068 "joystick controller" is not that "proprietary", but is using the Fuller standard internally/from the application point of view.
Also from the TS2068 Technical Manual, page 46, we can confirm the fire button it is indeed I/O port bit 7.
Table 2.4.4-1
Joystick Connectory Signal Assignment
Pin # Signal Name I/O Port Bit Function 1 *DIR1 0 STICK UP 2 *DIR1 1 STICK DOWN 3 *DIR1 2 STICK LEFT 4 *DIR1 3 STICK RIGHT 5 not used 6 *BUTTON 7 PUSH BUTTON 7 +5V 5 VOLT POWER 8 *READ_STB ADDRESS BIT 8 or 9* 9 GND POWER GROUND * When Address Bit 8 is high, the READ strobe to the left joystick is driven low.
When address Bit 9 is high, the READ strobe to the right joystick is driven low.
From the Timex/Sinclair 2068 Third Party Software Guide, page 3-5:
The joysticks used are industry-standard. They connect to a 9-pin "D-type" connector.
The byte read is interpreted as follows:
1 D0: 0 indicates stick up 2 D1: 0 indicates stick down 4 D2: 0 indicates stick left 8 D3: 0 indicates stick right 16–64 (D4, D5, D6): Not used (all ones) 128 D7: 0 indicates pushbutton depressed
You are reading it right. The schematics do not match the description.
According to the Timex/Sinclair 2068 Third Party Software Guide, it’s D7. 0 indicates the button has been pushed.
Also, here's the Timex tech manual (from Timex).
Here's the Timex tech manual (from Timex): https://archive.org/details/TimexSinclair2068Manuals/Timex%20Sinclair%202068%20Technical%20Manual%20%28best%29/
And their Third Party Software Guide: https://archive.org/details/timex-computer-corp/Timex%20Sinclair%202068%20Third%20Party%20Software%20Guide/
