I started the MBHP_TV as a new challenge to learn something new (e.g. to find a solution for an isochronous system which never gets out-of-sync), it’s another topic if a display with such a low resolution is usefull or not. But it awakes some vintage feeling - if MIOS would support a keyboard and a mass storage device (PRESS PLAY ON TAPE…), you would have a complete homecomputer
The fascinating thing on this project is that you can see the execution time of a routine directly on screen. Every pixel “consists” of 4 PIC instructions executed within 400 nS - I could also display a pixel with one instruction only, but the PIC18F452 doesn’t offer enough memory to store so much data.
However, the code is now released and can be found in the MIOS download section (still PAL only), the resolution is 128x64, only one character set is supported yet (but additional fonts could be included) - character size 8x8 (16x8 display)
Following SysEx commands are available:
; o Clear Screen:
; f0 00 00 7e 3f 00 00 f7
; o Set Cursor Pos and Print Characters:
; f0 00 00 7e 3f 00 01 <pos> <char_1> <char_2> ... <char_n> f7
; o Print Characters (don't set cursor):
; f0 00 00 7e 3f 00 02 <char_1> <char_2> ... <char_n> f7
The MBHP_TV module will be supported by the next MIDIbox LC version
Dan: you’ve to use the scart socket (A/V input of your TV)
Btw.: the next MIOS version will support a new display type #6 which redirects all print commands directly to the MIDI Out based on the new MBHP_TV protocol. By changing the device ID up to 128 “MLCDs” can be addressed in this way - not only the MBHP_TV itself, but also other “slaves” which support this protocol (example driver for a character LCD as slave will follow).
I also plan to include a “soft font” feature into the MBHP_TV which allows to create special characters dynamically like known from character LCDs - hold the line
Btw.: the next MIOS version will support a new display type #6 which redirects all print commands directly to the MIDI Out based on the new MBHP_TV protocol. By changing the device ID up to 128 “MLCDs” can be addressed in this way - not only the MBHP_TV itself, but also other “slaves” which support this protocol (example driver for a character LCD as slave will follow).
I can see it now…rows and rows of TV screens displaying SID parameters, sequences, routing paths, control data… ;D ;D *twitch* *twitch* I’m freaking out man!!
I read a little about this 2TV PIC on Rickards site and two things came to my mind:
First: Hey there is a gray scale, too! (just white, grey and black, but whatever) Can that be implemented into MIOS? Its just sending the signal to Port D1 and let D0 on mass. Possibility? But on the other hand: Usefull for MIOS? Perhaps…
Second: Rickard used a slow and little PIC16C84 with a 12 Mhz Oscilator. With a PIC18F (with lets say a 24 Mhz oscillator quadrupled to 48 Mhz) the signal would be sent four times as fast and so double the vertical and horizontal resolution (256x128!!! *freaking out again*), or not? Possible? To much work?
These are just some thoughts, but I`m just to hot about that TV thing!! So dammit cool!!! :D
hehe I think I’m going to try this this afternood!
maybe with a faster pic… more resolution?
But, is anybody here who know the “minitel”? it’s a french, old, phone terminal, with a small screen… maybe usefull as a MIOS screen (and cheaper than a tv)
The resolution isn’t limited by speed, but by the available RAM.
However, the next version will support a hires mode with quadrubled resolution which will only work with “ROM fonts” and with 1 pixel distance between the 8x8 characters. This will be nice as replacement for the MIDIbox LC display, since exactly 56 characters can be displayed per line in this way.
Grayscales: not possible since two pins cannot be stimulated at the same time when the shifting method (for highest speed) is used.
;D *twitch* *twitch* I’m freaking out man!!