AVI Hyperboard Expansion Card Assembly Notes
This page documents the detailed assembly notes for building the AVI ELF II Hyperboard Expansion Card.
The Hyperboard is a decendant of the Netronics ELF II Giant Board with modern enhancements for additional RAM and EEPROM, input/output ports and serial connections. If your goal is to have a replica of an expanded ELF II system with all of the bells and whistles of the late 70’s, the Hyperboard is a good addition.
This build page documents the assembly of the board and settings to use it with a variety of monitors and firmware old and new so that you can connect your ELF II to a terminal using a serial connection or use it with the Netronics Giant Monitor to save and load files from a cassette tape recorder.
Download the zipped archive of Gerber Files to produce your AVI ELF II Hyperboard Expansion Card. You can send this zipped archive to most PC Board Fabricators to have a set of boards created at a reasonable cost.
Please download the AVI Hyperboard Expansion Card Bill of Materials Excel spreadsheet to help you to acquire all of the components for the board. We have included links to all of the components that we were able to source from known electronics parts houses and have included notes for the components that may be difficult to find.
Note: This board contains several RCA or Intersil COSMAC components that are no longer in production. We have been able to source them for our prototype boards through EBay sellers.
We suggest that all integrated circuits for your AVI ELF II expansion cards are installed with high quality sockets. We have found that "cheap" turned pin machine sockets have failed us on more than one occasion. If you can't find affordable high quality machine sockets, then we suggest you rely on dual leaf sockets which are rarely known to fail.
The easiest way to build the AVI Hyperboard Expansion Card is to start small and move up. Begin your build with the smallest components and then start moving up to larger components. The entries below detail the order of component installation we have chosen for ease of construction.
Our build methodology begins with installing the 13-1N914 diodes. Gather the parts and bend the leads with with small needle nose pliers, then insert the diodes and tape them in place on the top of the board with masking tape to hold them in place while soldering and then remove the tape after the diodes are soldered in place. Solder the diodes as quickly as possible to avoid overheating and damaging them.
Note: If 1N914 diodes are unavailable, for our purposes 1N4148 diodes are a suitable substitute.
After the diodes, resistors are the next smallest components so they are next to be installed. Use the same method you used to install the diodes as you use with the 22 resistors on the board.
Note: There are 2 resistor networks to install on the board but we tend to install resistor networks later during the build after all of the lower profile components have been installed.
The 8 ceramic capacitors that populate the board are the next smallest components after the resistors so they are the next components to install. The shape of the capacitors make them a little tricky to solder in vertically but with some care and attention they should be reasonably simple to install. Take care not to overheat the capacitors when you install them. It should only take a fraction of a second to solder each end with a good soldering iron and good quality solder.
We have taken care with the AVI Hyperboard Expansion Card board to orient all IC's consistently. All vertical IC's are oriented with the notch locating pin 1 up. Please take care to install your IC sockets and IC's accordingly.
In my builds I have socketed the crystal oscillator so that I can swap it out if I need to. I created a socket for my board by sacrificing an 8 pin turned pin machine socket, removing 4 of the conductors, leaving and soldering the 4 corner pins for the oscillator.
Note: If you are not going to socket your Oscillator, now is about the best time to solder it in place. Make sure to orient it correctly to place pin 1 in the marked location.
Install the 2 resistor network components next (RN1-RN2). These resistor networks have a common pin which is often marked on the resistor network with a circle or solid dot. If in doubt, use an ohm meter to assess which pin is the common pin and take care when placing them to make sure that you have them oriented in the correct direction. RN1 has the common pin in the bottom location. RN2 has the common pin in the right side location.
Install the 8 LED's for Boot ROM, Status and Communications, taking care to make sure that they are oriented correctly. Typically, the negative lead of the LED is dignified by the flat side of the otherwise rounded lens and the negative lead is generally slightly shorter than the positive lead.
The jumper pins are made up from Breakaway Male Pins Headers that come in rows of 40 conductors that are easily snapped into headers of however many conductors you need. In this case we are using some that were purchased from Digikey but they are commonly available from most electronic supply houses.
Note: For J6 (Boot ROM Enabled/Disabled), we are using a micro sized SPDT switch. This allows us to switch between the run switch automatically booting the ROM or not. We purchased these switches from Amazon. They were describes as: "uxcell uxcell55 Pcs 3 Terminals PCB Mount 2 Position SPDT Mini Slide Switch"
The dual row pin headers are made up from Breakaway Male Dual Pin Headers that come in dual rows of 40 conductors on each side that are easily snapped into headers of however many conductors you need. In this case we are using some that were purchased from Digikey but they are commonly available from most electronic supply houses.
The last components to install are the two electrolytic capacitors. Be careful to ensure that you’re installing them according to their correct polarity.
If you have followed these build instructions, you should be able to install the IC's, crystal oscillator (if it's socketed) and when you plug it into the expansion slot on your AVI ELF II Rev D Variant, you’ll be able to run the card without any concerns. That said, it's probably a good idea to exercise caution and engage in a checkout routine before inserting all of the integrated circuits and applying power to the Hyperboard.
Without any of the integrated circuits installed, plug the board into the 86 conductor expansion socket on your AVI ELF II Rev D Variant. When you flip the power switch on, the Power LED should illuminate on your ELF II and it should function as it normally does. The LM 7805 should remain cool to the touch or just slightly warm and you should read 5v at the power/ground positions on the IC sockets of the Hyperboard.
If your tests confirm the above assertions, flip the power switch off, unplug the Hyperboard and populate the board with the integrated circuits from the bill of materials, taking special care to insert the correct components and their correct orientation for pin 1 of each device.
In order to use the Hyperboard, there are a number of jumpers that need to be set.
- On the AVI ELF II Main Board, below Expansion Slot 5 are two 3-pin headers. J9 & J11. If you are going to use the Hyperboard, jumper J9 needs to be set to "DISP ST" by placing a jumper shorting connector on the top and middle pins of J9.
- On the Hyperboard at the top left side are pin headers J6, J7, J8, J9.
- J6 can be jumpered to “Boot” from the EPROM Firmware when the RUN switch is turned on or to run whatever has been programmed in the program memory.
- J7 can be jumpered to ignore the main board RAM and use the RAM on the Hypercard.
- J8 is used to set the RAM low and EPROM high or the EPROM low and the RAM high.
- J9 is used to configure for a 27C256 EPROM or a 28C256 EEPROM
- If you are planning for bit/bang serial communications using the Q-bit for Tx and an EF line for Rx:
- Pin header J15 is used to configure EF port and Q settings.
- COM 1 on the right side of the board has connections for Rx, Tx and Ground for use with a USB TTL to Serial connector.
Note: On the board in the photo below, we have set the board to use an EEPROM programmed with Josh Bensadon's VELF Firmware. The jumpers are set as follows:
- Boot Enabled
- Disabled RAM on main board
- RAM Low (0000) / EPROM High (8000)
- 28C256 EEPROM
- Using COM1 for bit-bang serial Tx = Q, Rx = EF2 (non-inverted Q and EF2)
The firmware packages described below utilize a serial connected terminal to enable the use of advanced features that are included in the firmware. With the Hyperboard, you can connect to your ELF II to a computer running a terminal program (PC / Mac / Linux computer with a VT100 terminal emulator [Teraterm, Minicom, Serial, SCREEN, etc.]).
Serial bit-bang
The simplest but most common connection is a Bit-Bang Serial connection where a TTL/Serial USB adapter can be connected to the Hyperboard on COM1 for Tx/Rx/Ground and the specific signals that the firmware requires are configured using J15. This typically involves setting the Tx signal to Q or inverted-Q and setting Rx to one of the EF lines either inverted or non-inverted. In the photo above, the bit-bang serial configuration is set to use Q non-inverted for Tx and EF2 non inverted for Rx.
The COM1 Serial Connections are as follows:
- Tx from COM1 on the Hyperboard connects to Rx on your TTL/Serial USB adapter.
- Rx from COM1 on the Hyperboard connects to Tx on your TTL/Serial USB adapter.
- GND (Ground) from COM1 on the Hyperboard connects to GND on your TTL/Serial USB adapter.
Using the CDP1854 with the CDP1863 Frequency Generator
More to come...
Using the CDP1854 with a CD4040 Frequency Generator
More to come...
The following entries describe how to use your ELF II with the AVI Hyperboard expansion card to use a variety of widely available CDP1802 software/firmware monitors and utilities.
The AVI ELF II and Hyperboard can be configured to be used with Josh Bensadon's VELF Firmware which provides serial terminal communications at 9600 BAUD (8N1 - 8 bit, Parity None, 1 stop bit with no flow control) to provide a useful terminal connection to Enter, Inspect and RUN programs on your AVI ELF II. The VELF Firmware also contains the Giant Board Monitor to enable you to use your ELF II as a period correct, expanded ELF II from the late 70's.
To use the VELF software with your AVI Hyperboard in the AVI ELF II, you will need to have your ELF II main board configured as follows:
- Jumper J3 to "I61" by placing a jumper shorting connector on the left and middle pins of J3.
- Jumper J9 to "EF1" by placing a jumper shorting connector on the bottom and middle pins of J9.
- Jumper J11 to "I69" by placing a jumper shorting connector on the top and middle pins of J11.
You will also need to set the jumpers for a serial connection using Teraterm or other VT100 emulation on a PC, Max, Linux terminal, as described above.
You will need to set your Hyperboard memory settings at J8 to place RAM Low and ROM High. It may also be necessary to un-jumper the jumper point at J7.
For the serial connection, you will need to set the jumpers on your Hyperboard for bit-bang serial connection on Q/EF2. Set J15 on the Hyperboard to connect Hyperboard COM1 (top right side) to Q non-inverted for Tx and EF2 non inverted for Rx; a TTL/Serial USB adapter can be connected to the Hyperboard on COM1 for Tx/Rx/Ground.
The VELF software contains 3 commands:
- D: Dump a block of memory
- E: Enter code at a specific stating address; each op code is entered when it’s typed in and the address is automatically incremented to the next nibble. Press esc to return to the VELF monitor.
- R: Run from a specific starting address.
Note: The VELF Firmware is CASE SENSITIVE, meaning that the commands and Data (addresses/op codes) must be entered in UPPER CASE.
More to come regarding using the CDP 1854 UART with VELF.
The AVI Hyperboard was conceived by Ed Keefe as a modern variant of the original Netronics Giant Board with the intention of running the Giant Monitor, a 256 byte monitor program capable of tape read and writes, memory examine, modify and execute. The Giant Monitor does not require a serial terminal connection and all commands are run through the toggle switches and Hex Keypad. This is elite computing circa 1976.
To use the Netronics Giant Monitor with the AVI Hyperboard, you will need the 256 byte Giant Monitor which will need to be located at address F000 (included in Josh Bensadon's VELF firmware) and you will need a copy of the Netronics "Giant Board" Assembly Instructions which describes the feature set and usage of the Giant Monitor.
You can find a PDF of the Netronics "Giant Board" Assembly Instructions in the Files area at the COSMAC ELF Group (requires signup/login to access the files). Link to the "Giant Board" Assembly Instructions in the Files area
If you have programmed the firmware ROM on your Hyperboard with Josh Bensadon's VELF firmware, then the Giant Monitor is included at the correct address and can be accessed by executing a long jump to address F000. There are several ways you can execute a long jump to the Giant Monitor within the VELF firmware.
- You can manually execute the long jump by disabling the "boot" feature on the Hyperboard (J6) and programming your ELF II to execute a long jump to address F000 using the following op codes: C0 F0 00. When you switch the ELF II to RUN it will execute the jump and the ELF II will be under the control of the Giant Monitor.
- You can use the VELF firmware to R (Run) and enter F000 as the address.
- You can use the VELF firmware to E (Enter) the long jump at location 0000, enter the op codes C0 F0 00 and then R (Run) location 0000.
You can test the features of the Giant Monitor by running the tests described in the Giant Board Assembly Manual PDF linked above.
From the Giant Board Assembly Manual:
To enter the monitor program, turn off the Run, Load and M/P (memory protect) switches to reset the 1802. Place the load switch in the on position and, using the keypad, enter C0 F0 00. Set the load switch in the off position. When the Run switch is turned on, the monitor will come into play. The next input will determine the monitor mode: 00 is execute, 01 is memory examine, 02 is memory change, 03 is cassette write, 04 is cassette read, and 05 is memory scan.
To execute (run) a program from a memory location other than 0000, enter the monitor (C0 F0 00), and then enter 00. Insert the two-byte address of the beginning location. When the Input switch is depressed, the program executes from the memory location specified.
To examine a memory location, enter the monitor and key in 01. Insert the two-byte address of the memory to be examined, then depress and release the Input switch. The byte stored at that memory location will be displayed. Depress and hold the Input switch down and the low-order address of the next byte is displayed, followed by the memory byte when the Input switch is released.
To change data at a memory location, enter the monitor then enter 02. Insert the two-byte address of the memory to be changed and note that the Q LED comes on. Enter the new data. Then depress and release the Input switch. The new byte will then be displayed. Note that the low-order address of the next byte is displayed if you hold the Input switch down. If desired, that byte can also be changed. Loading and checking programs thru the monitor allows easy identification of addresses and corrections.
To cassette write, enter the monitor the enter 03. Key in the starting two-byte address of memory to be recorded, then key in the ending two-byte address. Place the tape recorder in the record mode, allow several seconds for the leader to pass the heads, and then depress the Input key. The Q LED will extinguish when the recording is complete and the low-order ending address will be displayed. The tape output of the ELF is connected to the microphone input on your tape recorder.
To cassette read, connect the speaker terminals of your tape recorder to the tape input on the ELF II, enter the monitor and then enter 04. Enter the two-byte address of the memory to be loaded. Then enter the ending two-byte address. Put the cassette recorder in the playback mode and depress the input switch. Allow 2.5 seconds for each 256 memory bytes recorded. The display will increment the low-order address of memory being entered. When the display stops incrementing at the last low-order address, the playback is complete. The final digits in the display will show the low-order address of the data being written (recorded).
To perform a memory scan enter the monitor and then enter 05. Enter the starting address (two-byte) of where you want to begin the search, and then enter the byte that you are searching for; depress the Input switch twice holding it down the second time. The display will now indicate the first low-order address that the byte appears in memory. Releasing the Input key will then show the contents of the memory at that location. The monitor is now automatically in the examine mode.
If you are in the monitor program and select an illegal operating code (other than those spelled out above), an EE will be displayed on the readouts and the Q LED will come on.
The AVI ELF II and Hyperboard can be configured to be used with Robert Armstrongs's STG ELF 2K Firmware which provides serial terminal communications at 2400 BAUD 8N1 (8 bit, Parity None, 1 stop bit with no flow control) to provide a useful terminal connection to use the STG ELF 2K software on your AVI ELF II.
You will need to set your Hyperboard memory settings at J8 to place RAM Low and ROM High.
In order to run Robert Armstrongs's STG ELF 2K Firmware, you will need to set jumpers on the AVI ELF II main board as follows:
- Jumper J3 to "I61" by placing a jumper shorting connector on the left and middle pins of J3.
- Jumper J9 to "DISP ST" by placing a jumper shorting connector on the top and middle pins of J9.
- Jumper J11 to "I69" by placing a jumper shorting connector on the top and middle pins of J11.
For the serial connection, you will need to set the jumpers on your Hyperboard for bit-bang serial connection on Inverted Q and Inverted EF3. Set J15 on the Hyperboard to connect Hyperboard COM1 (top right side) to Q inverted for Tx and EF3 inverted for Rx; a TTL/Serial USB adapter can be connected to the Hyperboard on COM1 for Tx/Rx/Ground.
When you flip the run switch from RESET to RUN on your ELF II, the STG Firmware will run a system check and the status codes will be displayed on the data LED's. If the firmware runs into an issue, a status code will be displayed and you can look up the reason in the STG ELF2K Manual (available on the STG website). When the data LED's display the Hex code 16, the system is waiting for you to press a key on your terminal keyboard. When you press a key, you will receive the following message in your terminal window:
COSMAC ELF 2000 EPROM V120 CHECKSUM F0CB SRAM 32K INITIALIZED
Copyright (C) 2004-2020 by Spare Time Gizmos. All rights reserved.
ElfOS BIOS Copyright (C) 2004-2020 by Mike Riley.
Typing HELP will bring up the STG Firmware Feature-set and Programs
| PROGRAM CONTROL COMMANDS | |
|---|---|
| B[oot] | -- Boot ElfOS disk operating system |
| CALL addr | -- CALL an application program w/SCRT (P=3) |
| RUN [addr] | -- RUN an application program (P=0) |
| CONT[inue] | -- continue after a break point |
| BUILT IN LANGUAGES | |
|---|---|
| BAS[ic] [NEW|OLD] | -- rc/BASIC L2 interpreter |
| FOR[th] [NEW|OLD] | -- rc/Forth interpreter |
| ASM [NEW|OLD] | -- interactive editor and assembler |
| VI[sual] | -- Visual/02 interactive debugger |
| SED[it] | -- disk sector editor |
| MEMORY AND I/O COMMANDS | |
|---|---|
| E[xamine] addr | -- examine one byte |
| E[xamine] addr1 addr2 | -- dump a range of bytes |
| D[eposit] addr data [data ...] | -- deposit data in memory |
| IN[put] port | -- read data from an I/O port |
| OU[tput] port data | -- write data to an I/O port |
| :llaaaattdddd..cc | -- load an INTEL hex record |
| SET COMMANDS | |
|---|---|
| SE[t] Q [0|1] | -- set or reset Q output |
| SE[t] DA[te] mm/dd/yyyy hh:mm:ss | -- set RTC date and time |
| SE[t] RES[tart] [addr|BOOT|NONE] | -- set power on action |
| SE[t] NVR DEFAULT | -- initialize NVR to default values |
| SHOW COMMANDS | |
|---|---|
| SH[ow] CPU | -- show CPU type and speed (requires RTC) |
| SH[ow] DA[te] | -- show current date and time |
| SH[ow] DP | -- show monitor data page |
| SH[ow] EF | -- show status of all EF inputs |
| SH[ow] IDE | -- show all IDE devices |
| SH[ow] MEM[ory] | -- show amount of BIOS memory |
| SH[ow] NVR | -- show contents of the RTC/NVR chip |
| SH[ow] TERM[inal] | -- show console port and baud rate |
| SH[ow] REG[isters] | -- show registers after a breakpoint |
| SH[ow] RES[tart] | -- show restart option |
| SH[ow] VER[sion] | -- show monitor and BIOS version |
| TEST COMMANDS | |
|---|---|
| TE[st] RAM | -- exhaustive test of system RAM |
| TE[st] PIX[ie] | -- test CDP1861 video subsystem |
| OTHER COMMANDS | |
|---|---|
| HEL[p] | -- print this text |
| CLS | -- clear VT1802 screen |
| ; any text | -- comment command procedures |
| ^C | -- cancel current command line |
| <BREAK> | -- interrupt execution of long commands |
| STARTUP SWTICH OPTIONS | |
|---|---|
| 0 1 0 0 0 0 1 0 | -- force SRAM to be initialized |
| 0 1 0 0 0 0 1 1 | -- force SRAM and NVR both to be initialized |
More to come...
Experimental
Lee Hart's MemberCHIP firmware was designed to run on a minimalist 1802 microcomputer platform running at a clock speed 4MHz which is just over twice the speed of the 1.79MHz ELF II clock. The clock speed of the CPU is used to generate the appropriate BAUD rate that the software requires for terminal connection so a slight non-permanent modification is necessary if you choose to run the MemberCHIP software on your ELF II.
To get the ELF II up to speed, you will need to remove the 74HC74 (A16) that is used as a frequency divider and insert a jumper in the A16 socket to connect pins 3 to 5. This will disconnect the 1861 graphics chip from the clock and will send the full 3.579545MHz clock signal directly to the 1802 which is just fast enough to be compatible with the MemberCHIP software.
Note: If you perform the mod described above, your CPD1861 Pixie display circuit will be disabled until you remove the jumper from A16 and reinstall the 74HC74 chip.
Visit Lee Hart's website to learn about The 1802 MemberCHIP Card Microcomputer and the MemberCHIP software.
The AVI ELF II and Hyperboard can be configured to be used with Lee Hart's MemberCHIP Firmware which provides serial terminal communications at 4800 BAUD 8N1 (8 bit, Parity None, 1 stop bit with no flow control) to provide a useful terminal connection to use the MemberCHIP software on your AVI ELF II.
To use the Lee Hart's MemberCHIP Firmware with your AVI Hyperboard, you will need to have your ELF II main board configured to use the expansion card by setting jumper J9 to "DISP ST" as described above in the section on Jumper Settings.
You will need to set your Hyperboard memory settings at J8 to place ROM Low and RAM High as described above in the section on Jumper Settings.
For the serial connection, you will need to set the jumpers on your Hyperboard for bit-bang serial connection on Q/EF3. Set J15 on the Hyperboard to connect Hyperboard COM1 (top right side) to Q non-inverted for Tx and EF3 non inverted for Rx; a TTL/Serial USB adapter can be connected to the Hyperboard on COM1 for Tx/Rx/Ground. The photo below illustrates the settings that configure the Hyperboard to use a 27C256 EPROM with the MemberCHIP firmware on an ELF II system.
Note: You will need to disable the auto boot feature on your Hyperboard in order to allow your ELF II computer to execute the instruction code on the MemberCHIP ROM when you toggle the run switch up. After you toggle the Run switch to the Run position, press any key to activate the program; the terminal will print a welcome message. Type an upper case H for the command menu.
The MemberCHIP firmware ROM contains the following feature-set:
| Commands | Description |
|---|---|
| H | Help |
| B | BASIC level 3 v1.1 |
| P | Play Adventureland |
| L | Load program or data (Intel HEX format) |
| V | View 1802 registers |
| Daaaa bbbb | Disassemble Opcodes from aaaa to bbbb |
| Maaaa bbbb | Memory read from aaaa for bbbb bytes |
| Waaaa dd dd.. | Write to memory until |
| Saaaa bbbb | Save memory at aaaa for bbbb bytes (Intel HEX format) |
| Taaaa bbbb cccc | Transfer (copy) memory from aaaa to bbbb for cccc bytes |
| Raaaa | Run program with R0=aaaa, P=0, X=0, Q=1 |
All commands are UPPERCASE. All numbers are HEX. <ESC> aborts a command.
Experimental
With the Hyperboard configured as described above for use with Lee Hart's MemberCHIP Card firmware, we can also run Mike Riley's "Diskless" Firmware for MemberCHIP. At the time of this writing, the Pico ELF V2 "Diskless" Firmware we are using is MChipElfOSv173.bin which was written by Mike Riley with updates by Al Williams and Gaston Williams and compiled by Gaston Williams. It can be found on the Fourstix GitHub Repo and burned to a 27C256 EPROM or a 28C256 EEPROM. Get the firmware here.
The image below is a photo of the Hyperboard configured to use the MemberCHIP Card version of Mike Riley's Diskless OS. The ELF II is running with the 74HC74 bypassed so that it can run at 3.579MHz and the terminal BAUD rate is 4800.
Mike Riley's "Diskless" Firmware uses a number driven menu. After the computer is switched to RUN mode, press the Enter key on your computer running the terminal program to prompt the commands menu; then select the command that you would like to run.
Mike Riley's "Diskless" Firmware for MemberCHIP ROM contains the following feature-set:
| Commands | Description |
|---|---|
| 1. | Rc/Basic L2 |
| 2. | Rc/Forth |
| 3. | Rc/Lisp |
| 4. | EDTASM |
| 5. | VTL2 |
| 6. | Visual/02 |
| 7. | Minimon |
| 8. | Dump Memory |
| 9. | Load Memory |
Experimental
Mike Riley's Pico ELF V2 "Diskless" Firmware conflicts with the ELF II CDP1861 Pixie Video Chip. If you wish to run this firmware, you will need to remove the CDP1861 Chip from your ELF II main board. At the time of this writing, the Pico ELF V2 "Diskless" Firmware we are using is PicoDisklessOSv173.bin which was written by Mike Riley with updates by Al Williams and Gaston Williams and compiled by Gaston Williams. It can be found on the Fourstix GitHub Repo and burned to a 27C256 EPROM or a 28C256 EEPROM. Get the firmware here.
In order to run Mike Riley's Pico ELF V2 "Diskless" Firmware, you will need to set jumpers on the AVI ELF II main board as follows:
- Remove The CDP1861 Chip
- Jumper J3 to "I61" by placing a jumper shorting connector on the left and middle pins of J3.
- Jumper J9 to "EF1" by placing a jumper shorting connector on the bottom and middle pins of J9.
- Jumper J11 to "N0" by placing a jumper shorting connector on the bottom and middle pins of J11.
For the serial connection, you will need to set the jumpers on your Hyperboard for bit-bang serial connection on Q (non-inverted) and EF2 (non-inverted). Set J15 on the Hyperboard to connect Hyperboard COM1 (top right side) to Q non-inverted for Tx and EF2 non-inverted for Rx; a TTL/Serial USB adapter can be connected to the Hyperboard on COM1 for Tx/Rx/Ground. The terminal BAUD rate should be set to 2400 BAUD.
The image below is a photo of the Hyperboard configured to use Mike Riley's Diskless OS for Pico ELF V2. The ELF II is running without the CDP1861 Pixie Display Chip.
Mike Riley's "Diskless" Firmware uses a number driven menu. After the computer is switched to RUN mode, press the Enter key on your computer running the terminal program to prompt the commands menu; then select the command that you would like to run.
Mike Riley's "Diskless" Firmware for Pico ELF V2 ROM contains the following feature-set:
| Commands | Description |
|---|---|
| 1. | Rc/Basic L2 |
| 2. | Rc/Forth |
| 3. | Rc/Lisp |
| 4. | EDTASM |
| 5. | VTL2 |
| 6. | Visual/02 |
| 7. | Minimon |
| 8. | Dump Memory |
| 9. | Load Memory |
The Hyperboard has been extremely stable however since it is a bit of a jack of all trades card for experimentation using software that was designed for other platforms, there is always the opportunity for gremlins to show up. We will monitor and document any issues we find as they come up.
During testing with a variety of firmwares we discovered that when a serial connection requires an inverted Q and/or EF line, the serial can become erratic and undependable. The issue appears to be surrounding the Integrated Circuit A6, a CD4069 hex inverter. If you find that your terminal sessions become unstable or that the screen commands and responses become garbled, replace the CD4069 with a 74HC04. Our experience has been that this will clear up the issue.
Happy Computing!!