Jump to content


  • Content Count

  • Joined

Community Reputation

684 Excellent

1 Follower

About alex_79

  • Rank

Contact / Social Media

Profile Information

  • Gender
  • Location

Recent Profile Visitors

19,636 profile views
  1. It has been reported a few times in the past that the pitch of the PItfall II music varies from one cart to another due to tolerances (and aging) of the components of the oscillator circuit. I remember someone also noticed that the same cart had different pitch when played on different consoles. As stated by batari a few posts above, the pitch of the harmony cart DPC was chosen to match the cartridge he used for testing. Check out this video:
  2. The grounded pin I was referring to in that old thread is on the 6532 RIOT chip, not TIA. On NTSC and PAL consoles, pin 21 of the 6532 is wired to the "TV TYPE" switch, which grounds the pin when in B&W position, while leaves it floating in "COLOR" position. The status of the pin can be read by the console and early games used it to select a palette optimized for B&W Televisions, while later games either ignored it or used it for other purposes. On a SECAM console that pin is grounded and not connected to the TV TYPE switch (that switch on SECAM consoles actually disables the color generation and its status cannot be read by the software). Therefore PAL and NTSC games played on a SECAM consoles will always "see" the TV TYPE switch as if it's in B&W position. Connected to the TIA:
  3. I only have very basic knowledge about electronics, so I can't be of much help on this. What I know is that some SECAM boards revisions use a PAL TIA, some other a NTSC one. The colors are generated based only on the 3 LUM pins by extra circuitry on the board, the TIA COL pin is not used. In theory you could convert your SECAM console into a PAL or NTSC one (depending on what TIA is installed on your system), but that requires replacing the crystal oscillator (and for PAL you need a second oscillator for color) and recreating the video circuitry using the PAL or NTSC schematic as reference. CX2600P_Official_schematic.pdfCX2600-CX2600A_Official_schematics.pdf In this thread, there's some info on the COL pin that might be useful: Tia schematics (NTSC) can be found here. From that list, Bump'n'jump, RealSports Soccer, Realsports Boxing, Pole Position, Jungle Hunt, Centipede, Forest and Ms. Pac-man are unaffected by the TV TYPE switch and display always in color in PAL and NTSC consoles (that is, you should have a signal on the COL pin of the TIA chip). "Off The Wall" uses the TV TYPE switch to pause the game. On a Secam console you can't access the pause feature in this game, but it is playable. It also displays always in color on PAL and NTSC systems.
  4. Send a PM to user batari or email him at c9r AT hotmail DOT com. Give him a few days to respond (he's a busy guy!)
  5. I don't know if this is of any relevance, but I noticed that the page loads almost instantly if I logout and browse the forums as guest.
  6. On older Stella versions the phosphor mode just merged frames in pair, which effectively completely eliminated any 30Hz flicker, but also caused fast moving objects to look bad. Since Stella 5.0, though, the phosphor mode was rewritten to more accurately represent the phosphor decaying of a crt screen and I keep it enabled for all games now. Contrary to the old effect, the new one doesn't suppress the flicker (so you still see what the program is doing), it just looks more like on a real CRT. In addition, bright objects moving on a dark background leave a faint trail, which is something I always liked when playing on old Tv sets. Note that I use the standard PC version, and have no experience with the libretro port. Things might be different there.
  7. Seems like your setup is displaying at 30Hz, skipping every other frame. And since the game flickers the player and enemies shots on alternating frames, you're only seeing either one or the other.
  8. I found several revisions of this hack. Which one are you testing? E.g. the rom in this page glitches if the decimal flag is set at power-on, but this bug has been corrected in subsequent revisions: In the first post of this thread there's a link to the latest version, which correctly initialize the decimal flag. If you burn the rom on a real cartridge (or flash the harmony cart in single game mode, so that the system is not initialized by the harmony menu), the glitch can occur on real hardware as well. (see here for another example)
  9. I've been asked if I could share the docs I have about this programmer, so here they are: Digelec_804_16k-32k_RAM_Expansion_Installation.pdf Digelec_804_IBM_AT_connection_ERRATA_0389.pdf Digelec_804_Schematics.pdf Digelec_804_sim_cable_2764-27128-27256.pdf Digelec_August_1988_Brochure.zip Digelec_Model_804_3.32_Update_Info.pdf Digelec_Model_804_4.12_Update_Info.pdf Digelec_Model_804_Brochure.zip Digelec_Model_804_Manual-1985.pdf Digelec_Model_804_Manual-1986.pdf Digelec_Model_804_Programming_Guide_Feb_88.pdf Digelec_Model_804_Programming_Guide_Nov_89.pdf Digelec_Model_804_Remote_Mode_Update_Dec_1989.pdf Promicron_2000-2100_Manual_1986_GER.pdf Promicron_2000-2100_Manual_1990_GER.pdf Promicron_celink_GER.pdf Apart for the german 1986 Promicron 2000 manual, which I scanned as it was included with my unit, the rest of these were sourced online from various places. I have them in djvu format with searchable OCR text, which also results in smaller files and it's the file type I like to use for scanned documents. Anyway, I converted them to pdf (and jpeg for the color brochures) for uploading here. OCR text has been lost in the conversion, though. If anyone is interested in the djvu versions, just ask here and I will upload them too. It's been a while since I last used the programmer, so I don't remember all the details, but I found these notes that I wrote years ago with the intention to post them here, but in the end I never did as I felt there was no interest in this device. ---------------------------- The ep804 is an eprom programmer and eprom emulator which consists of a z80 based computer. It can operate in stand-alone mode using the control panel or remotely from a PC through a serial connection. The rom image is stored in RAM before burning it to eprom and can be manipulated directly using the programmer (from the control panel or the remote PC). The amount of ram installed varies depending on hardware revisions and year of production and can be expanded. (mine has 16k of ram which can be expanded up to 32K). This refers to the ram portion that is used to store the rom images (to be burned on eproms or of the eprom emulator); there's an additional 2kb ram chip used by the z80 cpu to run the firmware. You can select the eprom address range that you want to program, so you can burn eproms which are bigger than the installed ram by programming them in multiple steps. At power-on the programmer will display a "POWER FAILURE" message. That's normal, it just means that previous settings are lost and reverted to default values, because there's not battery backed memory or other permanent storage in the unit. Press "CLR" to start the SELF CHECK procedure. If successful, the display will show "TEST OK mmmm vv", where "mmmm" is the max RAM address available and "vv" the firmware version number. I have 16Kb of RAM and firmware version 2.1 ----------------------- Connection cable: To connect to the PC you use the rs232 port located in the upper left corner of the control panel. The programmer needs a crossed (NULL MODEM) cable wired for full hardware handshaking. It has a female DB-25 connector, while usually a male DE-9 connector is used for the PC serial port (also on usb-to-rs232 adapters), so in most cases you need a male DB-25 to female DE-9 cable. Here's the pinout if you want to build it yourself. DB-25 M DE-9 F 1 ------ shield 2 ------ 2 3 ------ 3 4 ------ 8 5 ------ 7 6 ------ 4 7 ------ 5 20 ------ 6 Some cheap usb to serial adapters lacks the signals required for harware handshaking. In this case you can use a NULL-MODEM cable wired for "loop back handshaking", but you might have to decrease the transmission speed to have reliable transfers. Better yet, get yourself a quality usb serial adapter or install a real serial port if you have a desktop PC. Even if modern PC do not have the connector anymore, many motherboards still have headers connectors for serial (and often even parallel) ports, so you just need to install the external connector and enable the port in the bios in that case. More info on serial cables here: http://www.lammertbies.nl/comm/cable/RS-232.html ----------------------- Serial port settings: The default settings for serial connection are: 9600 baud 7O1 (7 bits, Odd parity, 1 stop bit). You can change that configuration by selecting the "initialize" function, but all settings are lost when you unplug the power cord. I just prefer using the default ones and set the PC serial port accordingly. ----------------------- Data format: Data is sent/received by the programmer in ASCII text format. So you can't send the eprom image as a binary file, but you must first convert it using one of the binary-to-text encodings supported by the programmer. The format can be selected with the "initialize" function, and as with the serial port settings, I use the default one that is "Intel HEX". There's plenty of file converters, with GUI or command line, either as standalone tool or integrated in other software (like HEX editors) so just search one for your operating system that suits your taste. On Linux, I use srec_cat, which is part of the SRecord package. If I have a binary file called "rom.bin" I convert it into the Intel HEX file "rom.hex" compatible with the programmer by typing the following command: srec_cat rom.bin -binary -output rom.hex -intel -output_block_size 16 -address-lenght=3 And this is for converting from HEX to bin: srec_cat rom.hex -intel -output rom.bin -binary ----------------------- To connect to the ep804, you can use a terminal emulator (I use minicom. A common choice on Windows was Hyper Terminal, but I don't know if it's still available on current windows versions). Connect the cable, set the correct serial port and configure it with correct baudrate, framing, parity and stop bits (9600 7O1 in case of the default values, as stated above) and turn on the programmer. You can control the programmer entirely from the terminal by selecting the "Remote" function. See the User Manual for a list of all the commands. You should turn on the "local echo" of characters either on the terminal emulator software or on the ep804 (use the "initialize" function for that) or you won't see what you're typing. Anyway, I prefer the "Key" mode, where you use the control panel on the programmer itself and just need the serial connection to send and receive the rom images. In this case I just use the linux shell to send the hex file directly to the serial port instead of the terminal emulator. First I set the serial port (/dev/ttyS0 in this example) with the correct parameters using stty: stty -F /dev/ttyS0 cs7 parenb parodd -cstopb -icrnl -onlcr crtscts Then I can do cat rom.hex > /dev/ttyS0 to send the file, and cat /dev/ttyS0 > rom.hex to receive. By using the serial port as input or output file in srec_cat I can avoid generating the intermediate Hex file and I work directly with binary: to send: srec_cat rom.bin -binary -output /dev/ttyS0 -intel -output_block_size 16 -address-length=3 to receive: srec_cat /dev/ttyS0 -intel -output rom.bin -binary Of course I don't type all that stuff every time. Instead I wrote 2 simple bash script called "upload_ep804" and "dump_ep804". so all I have to do is upload_ep804 rom.bin or dump_ep804 rom.bin to send and receive data respectively. ----------------------- Eprom simulator: The large 37 pin d-sub connector on the lower left of the control panel is labeled "SIM" and it's used for the "Eprom simulator" function. By building the appropriate cable for the kind of eprom you have to emulate (pinout is printed on the control panel itself, and can also in the manuals), you can connect the programmer in place of an eprom and test your code without the need to erase and reprogram chips. I used this feature to test games on some consoles for which I don't own a flash cartridge, such as an Interton VC4000 and a Videopac. Just set the programmer to the correct eprom type, then upload the data (from serial port, or by reading a rom/eprom plugged in the zif socket), then press the "SIM" Key on the programmer. At this point you can power on the target device that will read the data as if it was programmed in a real chip.
  10. A while ago I posted some info about color bar generator here:
  11. Check this file. Alternatively, load the rom in Stella and press ALT+L to display info about the rom, including size and bankswitching type. None. While Atari had the rom chip manufacturers include the bankswitching logic in the same package as the rom, standard eproms don't have that functionality and you have to implement it separately. Even if you reuse an existing Defender II cartridge board, you can't just replace the rom chip with an eprom. You can only use an old stock Atari SARA chip for that. The 2600 lacks clock signals on the cartridge port to easily interface standard ram chips. Atari and third party video game companies had to design their own chips to add extra ram on cartridges. Nowadays, homebrews requiring extra ram typically use an arm chip that emulates rom, ram and bankswitching, like the melody board For testing your hack on real hardware, consider getting an Harmony, or a UNO cart.
  12. alex_79


    The full version was posted last year (link), but currently attachments are not visible due to forum upgrading. You have to wait a few days until the background conversion tasks complete.
  13. I think that the light blue/gray bubbles indicates no new content in a topic you have participated in, while no bubbles at all is no new content in a topic you have not participated in.
  14. What you mean by "weird"? can you post a picture of it? The NTSC firmware will work just fine in a PAL system+TV (unless your TV doesn't support a 60Hz signal, in which case the screen will roll). It will just show different colors (blue text instead of green) in the menu. The games are not affected.
  • Create New...