 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : PicoGAME Alpha - advance info
| Author | Message | ||||
Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
PicoGAME Alpha won't be fully compatible with previous releases for several reasons. I want to try some new ideas. * Uses a normal PicoMite VGA, not a special version. * Same "mini" RTC fitted. * Same physical size as before, but there is no need to hack the sides of the enclosure (unless you want a hole for an reset button). * Alternative reset button position allows access through a hole in either the top or the bottom of the case. The PCB has a guide hole to get the position correct. * The voltage regulator can be either the Microchip device used previously or the LM1117 (through hole packages only). * The SDcard socket is standard size only. * The audio side now uses the PDIP packaged version of the MCP4822 family. The 3.5mm audio jack is on the rear. * The VGA socket is a RJ45. This may seem an odd choice but adapters are very easy to get and cheap. It means that there should be no problem in getting a socket. The magic of twisted pair allows at least a couple of metres of lead at 640x480 if you wish. * There are two 6P6C sockets, one on the front and one on the back. These are connected in parallel and can accept either an I2C-connected controller or a PS2 keyboard. Once again, an odd choice and a DIY adapter will be needed for a keyboard unless it's rewired, but you can use two controllers and no keyboard if you wish. You can also plug the keyboard into the front socket if you wish. You could also make a little adapter to connect both controllers into a single socket and keep all three connected. The I2C voltage level is 3V3 (with pullups on the PCB) but +5V is available on the connector for the keyboard. If a remote I2C device requires 3V3 power it will need its own regulator from this supply. * There is a position for a JDY-40 wireless module with its IO pins connected to GP0. GP1, GP2, GP3, GP10, GP11, GP12 and GP13. A set of links on the PCB allows it to be temporarily connected to the same connections as the SDcard but on COM2 so that it can be set up. The 8-pin connection allows... * Option to use a very simple wireless controller with up to 8-switches. This will be battery operated with a very low standby current (5uA) so it doesn't need to be rechargeable. * A strip of 6 WS2812B LEDs runs across the PCB. This should be particularly effective if the board is housed in the translucent blue enclosure. :) These are powered from their own supply diode from the power input socket. * Power input is via the usual barrel jack. If this is used as a supply then the LED strip isn't powered as it may present too much load to the USB supply. I currently envision the I2C controllers to be of two types. 1: Simple "button" controller with up, down, left, right and three aux. buttons. One spare input. 2: Insanely stupid controller using a 2-axis thumb joysick fed into a RP2040-Zero together with three buttons. The RP2040-Zero would be an I2C slave and could be programmed to work as either an analogue joystick or a digital one. With the links for the JDY-40 fitted you lose all use of the SDcard. However the JDY.40 is now connected to COM2, with CS on GP6 and SET on GP7 so you have full control over it. It can be used as a wireless serial port at up to 19200 baud in this mode. No release date yet. I'm still playing with some aspects of the design. Edited 2023-06-06 23:21 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
Progress report The idea of using RJ45 for VGA seems to be excellent. I've had a decent display over a 3m length of ordinary unscreened CAT5 cable. I'm happy with that. Of course, only one RJ45 to VGA male is required. The mini joystick for the insanely stupid controller is giving better results than I'd hoped for. I've now got a controller box and some buttons to house it in when I get round to building it. I have a second controller box and even more buttons to make the wireless controller, but I'm waiting for a battery holder before I can start that. I have JDY-40 modules but they still need configuring. PCB design is almost there, I think. I'm holding on for the moment though. I fell into the trap of using low profile RJ12 connectors and had to make changes to fit more standard ones. If you are playing with these, the low profile pcb connections are a mirror of the standard connections as the plug connections are against the PCB rather than facing the top of the socket. Although they accept the same plugs they are not interchangeable on a PCB. That was something I wasn't expecting. I'd rather have used the low profile ones but they don't seem to be as popular with the big suppliers, although they are currently readily available on ebay, AliExpress etc. I might change my mind yet. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
 Print this page |
