DIY-Calculator Hardware:Community Portal
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| The '''DIY Calculator Hardware Project''' consists of several sub projects: | The '''DIY Calculator Hardware Project''' consists of several sub projects: | ||
| - | # Creating the real [[#Hardware Project|hardware]]: a printed circuit board ([http://en.wikipedia.org/wiki/Printed_circuit_board PCB]) with the processing chips, an LCD module, switches, and connectivity to a host computer | + | # Creating the real [[DIY-Calculator_Hardware:Hardware Project|hardware]]: a printed circuit board ([http://en.wikipedia.org/wiki/Printed_circuit_board PCB]) with the processing chips, an LCD module, switches, and connectivity to a host computer |
| - | # Implementing the DIY Calculator [[#FPGA Project| CPU]] together with supporting functional blocks within a programmable logic chip (a so-called "Field Programmable Gate Array" - [http://en.wikipedia.org/wiki/FPGA FPGA]). | + | # Implementing the DIY Calculator [[DIY-Calculator_Hardware:FPGA Project|FPGA]] together with supporting functional blocks within a programmable logic chip (a so-called "Field Programmable Gate Array" - [http://en.wikipedia.org/wiki/FPGA FPGA]). |
| - | # Writing the [[#ROM Monitor Project|firmware]] running on the hardware, including a [http://en.wikipedia.org/wiki/Read-only_memory ROM] monitor | + | # Writing the [[DIY-Calculator_Hardware:ROM Monitor Project|firmware]] running on the hardware, including a [http://en.wikipedia.org/wiki/Read-only_memory ROM] monitor |
| - | # Adding a [[#Upload Utility Project|software tool]] for communicating with the hardware (e.g. uploading user programs) | + | # Adding a [[DIY-Calculator_Hardware:Upload Utility Project|software tool]] for communicating with the hardware (e.g. uploading user programs) |
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| - | On this page you will find information about the progress of the project as well as technical details. | + | |
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| - | == Hardware Project == | + | |
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| - | [[Image:Blockdiagram.jpg|thumb|right|Blockdiagram]] | + | |
| - | The layout will somewhat resemble the layout of the (virtual) DIY Calculator with an 20x1 character LC display and a 70 keys sensor key matrix. Additionally there are connectivity means for a host PC: | + | |
| - | * Serial (RS-232) for uploading user programs and providing a console to the DIY Calculator CPU | + | |
| - | * A JTAG programming connector; this connects to the PC's parallel port and enables the user to load new designs into the FPGA | + | |
| - | * Additionally there will be sockets for external ROM/RAM chips and a large prototyping area for free use. | + | |
| <br style="clear:left;" /> | <br style="clear:left;" /> | ||
| - | Download the detailed schematics from here: [[:Media:schematics.pdf|Schematics]] | + | On the projects pages you will find information about the progress of the project as well as technical details. |
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| - | '''Project status''' (19.Jul.2006): schematics completed, PCB layout work started | + | |
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| - | '''Project status''' (7.Aug.2006): We decided to separate the functionality into two PCBs: the FPGA with surrounding components and the sensor keypad. This gives even more flexibility for different I/O modules. | + | |
| - | Here are the updated schematics: | + | |
| - | * [[:Media:Keypad_schematics.pdf|Keypad]] | + | |
| - | * [[:Media:Fpga_schematics.pdf|FPGA]] | + | |
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| - | '''Project status''' (13.Aug.2006): Prototype PCB layout completed. | + | |
| - | Here are the "final" schematics: | + | |
| - | * [[:Media:aq019_diycalculator_keypad_schematics.pdf|Keypad_Schematics]] | + | |
| - | * [[:Media:aq018_diycalculator_fpga_schematics.pdf|FPGA_Schematics]] | + | |
| - | keypad mechanics: | + | |
| - | * [[:Media:aq019_diycalculator_keypad_mechanics.pdf|Keypad_Mechanics]] | + | |
| - | and the layout: | + | |
| - | [[Image:Bare_fpga_pcb.JPG|thumb|left|Bare FPGA Board]] | + | |
| - | [[Image:Keypad-prototype.JPG|thumb|left|Keypad prototype]] | + | |
| - | * [[:Media:aq019_diycalculator_keypad_final_artwork.pdf|Keypad_Layout]] | + | |
| - | * [[:Media:aq018_diycalculator_fpga_final_artwork.pdf|FPGA_Layout]] | + | |
| <br style="clear:left;" /> | <br style="clear:left;" /> | ||
| - | Test of sensor keypad is in progress. | ||
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| - | '''Project status''' (31.Aug.2006): Test of sensor keypad was successful. | ||
| - | Here are the photos: | ||
| - | [[Image:Keypad_test1.jpg|thumb|left|Testing sensor pads]] [[Image:Keypad_test2.jpg|thumb|left|~3uS skew]] | ||
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| - | == FPGA Project == | ||
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| - | The PCB will contain an FPGA chip in the 10K-gates size-class (Lattice LFEC10E-3F256C) with a 256 pin BGA footprint. The included JTAG connector makes this a development board for general use. With ispLEVER, the FPGA development software suite from [http://www.latticesemi.com Lattice Semiconductor], the FPGA design can be altered or a completely new design can be made. The entry level version of ispLEVER ([http://www.latticesemi.com/products/designsoftware/isplever/ispleverstarter.cfm ispLEVER-Starter]) can be downloaded freely from Lattice. With Lattice's [http://www.latticesemi.com/products/designsoftware/ispvmsystem/index.cfm ispVM System] the design can be transferred via JTAG to the DIY Calculator PCB. | ||
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| - | The FPGA design of the DIY Calculator is based on the [http://www.diycalculator.com/popup-m-phyver.shtml work] of Steven Cooper, Carl Hoggins, Bjornar Prestegard, Svein Roar Kvaale, and Dr Albert Koelmans (instructor) of the University of Newcastle Upon Tyne, England. | ||
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| - | Additionally to the CPU and ROM and RAM there will be special logic for the switch matrix, for LCD output, and a UART for RS-232 communication to the host PC. | ||
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| - | '''Project status''' (19.Jul.2006): concept proved, integration of the existing VHDL design (was done with Altera/Quartus) into ispLEVER | ||
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| - | '''Project status''' (7.Aug.2006): Simulation of the existing CPU design revealed big troubles. A new design of the CPU is being made. | ||
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| - | '''Project status''' (31.Aug.2006): new CPU design is '''ready!''' (simulated and tested in a Lattice FPGA development board.) | ||
| - | [[Image:CPU_under_test.JPG|thumb|left|CPU under test...]] | ||
| - | Download the VHDL code from here: [[DIY-Calculator_Hardware:Downloads]] | ||
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| - | Next steps are design/integration of: | ||
| - | * LCD controller | ||
| - | * UART | ||
| - | * Keypad controller | ||
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| - | * stay tuned! | ||
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| - | '''Project status''' (4.Sep.2006): LCD controller works with CPU! See logic analyzer screenshot: [[Image:LCD-access.jpg|thumb|left| "Hello World" program accessing LCD]] | ||
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| - | Notice that there are two access cycles to the LCD module with each character, one which actually writes the character and a second one which shifts the display left, resembling the display behaviour of desktop calculators. | ||
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| - | Also note that during LCD accesses the CPU is effectively halted by the nWAIT signal which is generated by the LCD controller. Between LCD accesses there is activity on the CPU data and address bus, which indicates the loading of the next character, etc. View the "Hello World" program here: [[:Media:hello-tasm.lst|hello-tasm.lst]] | ||
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| - | '''Project status''' (6.Sep.2006): UART is working! See logic analyzer screenshots: [[Image:UART-tx.jpg|thumb|left| UART transmit character]] | ||
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| - | Note the "tx_empty" signal which denotes an empty transmitter register. During the shifting-out of the character tx_empty goes low thereby indicating that the CPU must not write a next character. The CPU is busy during this phase with polling the UART status register waiting for tx_empty going high again. tx_empty may trigger an interrupt request, if enabled by software. | ||
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| - | Line speed is 38.4 kbaud. | ||
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| - | [[Image:UART-rx.jpg|thumb|left| UART receive character]] | ||
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| - | Here the "rx_ready" is signal used for CPU handshake. When a character ('U' / $55 in the picture) is received rx_ready becomes high thus indicating to the CPU that a character is available n the UART for reading. When the CPU reads the character rx_ready goes low again. In the screen shot the CPU writes then the character to the LCD, which is easy recognizable as the CPU is halted during LCD access by means of the "nWAIT" signal. View the program listing here: [[:Media:uart-test.lst|uart-test.lst]] | ||
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| - | Line speed is (as with transmit) 38.4 kbaud. | ||
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| - | Here is a screen shot of a terminal session and a photo of the test board: [[Image:terminal-screen.jpg|thumb|left|Terminal screen]] | ||
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| - | [[Image:hello-world-on-LCD.jpg|thumb|left|"Hello World!" on LCD]] | ||
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| - | '''Project status''' (11.Sep.2006): Keypad cotroller implemented. During work on the ROM monitor it was necessary to complete the DIY Calculator with the keypad. While the real PCB being still not available the Lattice development board features 12 buttons organized in a 3 by 4 column / row fashion. The keypad controller is currently designed with this configuration but behaves at the DIY Calculator side exactly like the virtual version does and the real version will. See modelsim screenshot: [[Image:keypad.jpg|thumb|left| keypad controller]] | ||
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| - | Two key presses are simulated: first key '5' and then key '9'. See the scan rows changing (e.g. row1, row1_last) detecting changes and generating the 'key_set' signal which latches the respective key code. This in turn causes the KEYPAD input port to change from $FF to the key code ('d_out' signal). When the CPU reads from KEYPAD (short pulse on 'sel' line) a pulse on 'beep' signal is generated and the KEYPAD port value is reset to $FF. Note the (with the first key press) the '5'-key is still depressed when the CPU reads the KEYPAD but no additional key events are generated. In the second case ('9'-key) the key is released before the CPU reads KEYPAD. | ||
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| - | == ROM Monitor Project == | ||
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| - | On of the primary goals of the DIY Calculator project is to teach how computers are working on machine language level ("How Computers Do Math"). So everyone is highly encouraged to translate various algorithms into assembly programs for the DIY Calculator. The current virtual DIY Calculator comes with a ready-to-use environment, which includes the calculator-like user interface, an assembler, a simulator, single-step debugger, and memory and register display. When translating the design to a physical one there has to be an environment, too. The most important functionality (and this is the only one being in scope of this project) is to run user programs to the DIY Calculator hardware. To be able to do that there must be means of: | ||
| - | * uploading the program to the hardware | ||
| - | * store it in some non-volatile storage | ||
| - | * actually run it | ||
| - | * obtain some status information (e.g. terminated correctly, does not fit into memory, etc.) | ||
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| - | This is the objective of the ROM monitor. The ROM monitor is, as its name suggests, a program which resides within the ROM of the DIY Calculator. It is always present there and provides for the above mentioned supervising tasks. It uses the RS-232 port both for transferring the user program and as console port to which you can connect with a terminal emulation program (or a real "dumb" terminal if can get hold of one ..) to enter commands and display status information. The ROM monitor will be written in the DIY Calculator's assembly language and will additionally supply some basic functions (e.g. status/log output via RS-232) to user programs. | ||
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| - | '''Project status''' (19.Jul.2006): basic conceptual design ready | ||
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| - | '''Project status''' (7.Aug.2006): no changes | ||
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| - | '''Project status''' (31.Aug.2006): no changes | ||
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| - | '''Project status''' (6.Sep.2006): work started | ||
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| - | '''Project status''' (12.Sep.2006): First time that a program has been loaded an run to the DIY Calculator successfully! See terminal screen shot: [[Image:monitor-load.jpg|thumb|left| executing load and run command]] | ||
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| - | I loaded this program: [[:Media:keycode.lst|keycode.lst]], which waits for a key press and then displays the key code. Download the .ram file ([[:Media:keycode.ram|keycode.ram]]) and load it into your virtual DIY Calculator. In the real world you press buttons on the PCB and the codes are displayed on the LCD: | ||
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| - | [[Image:monitor-start.jpg|thumb|left| ROM monitor startup]] | ||
| - | [[Image:keycode-start.jpg|thumb|left| "keycode" program startup]] | ||
| - | [[Image:keycode-key.jpg|thumb|left| "keycode" program after pressing button '7']] | ||
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| - | Additional screen shots: [[Image:monitor-help.jpg|thumb|left| overview of available commands]] | ||
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| - | [[Image:monitor-md.jpg|thumb|left| memory display at $4000 (keycode program loaded)]] | ||
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| - | == Upload Utility Project == | ||
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| - | The user program upload process is handled by the ROM monitor on the DIY Calculator side. But there must be a means of sending a program to the DIY Calculator. While it is possible to send a file with the terminal emulation program a GUI program is preferable. Furthermore, by having a dedicated program for this task it is possible to generate a check sum or use a protocol of choice for ensuring correct transmission. The transmission status (success/failure) can be displayed. This program should be written in "C" using the GTK library of GUI widgets to be easily ported to different platforms. | ||
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| - | '''Project status''' (19.Jul.2006): considered | ||
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| - | '''Project status''' (7.Aug.2006): no changes | ||
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| - | '''Project status''' (31.Aug.2006): no changes | ||
Current revision
The DIY Calculator Hardware Project consists of several sub projects:
- Creating the real hardware: a printed circuit board (PCB) with the processing chips, an LCD module, switches, and connectivity to a host computer
- Implementing the DIY Calculator FPGA together with supporting functional blocks within a programmable logic chip (a so-called "Field Programmable Gate Array" - FPGA).
- Writing the firmware running on the hardware, including a ROM monitor
- Adding a software tool for communicating with the hardware (e.g. uploading user programs)
On the projects pages you will find information about the progress of the project as well as technical details.
