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%DASHBOARD{ section="dashboard_start" }% %DASHBOARD{ section="banner" image="%PUBURLPATH%/Cosmac/RaspiElf/raspi-elfmemcard-s.jpg" title="Serial EEPROMs as Mass Storage" titlestyle="color:#F00000;" }% %DASHBOARD{ section="box_start" title="Intro" width="485" height="200"}% Forth without mass storage (blocks, screens) is a not complete. A SD-Card [[http://www.elf-emulation.com/hardware/ide8.html][interface]] could be a reasonable solution but it is an overkill for a small Forth system. Small serial EEPROMs are for my opinion more suitable. %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" title="Contents" width="460" height="200"}% %TOC% %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" width="992" height="600" title="SPI EEPROMs " }% ---+ SPI EEPROMs The Serial Peripheral Interface [[https://en.wikipedia.org/wiki/Serial_Peripheral_Interface][SPI]] or four-wire serial bus is easy to use. The CDP1802 (MC) is the SPI master, the EEPROM is the slave. There are many different EEPROM types and sizes available e.g. [[http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-8832C-SEEPROM-AT25M02-Datasheet.pdf][AT25M02]] (2Mbit, 256 !KiB, $3), [[http://ww1.microchip.com/downloads/en/DeviceDoc/22064B.pdf][25LC1024]] (128 !KiB, $2), or [[http://ww1.microchip.com/downloads/en/DeviceDoc/20005265A.pdf][25LC512]] (64 !KiB, $1.50). All available in DIL8 packages. 64/128/256 !KiB seems very small for today's standards where storage is quantified in !GiB, but I think it's more than enough for a small Forth system, the size is similar to early floppy disks. If you want more memory there is 16 !MiB serial EEPROM [[http://www.winbond.com/resource-files/w25q128jv%20spi%20revc%2011162016.pdf][W25Q128J]] from WINBOND, please note that is a 3.3 V device! <verbatim> CLK MC ->- host MOSI MC ->- host MISO MC -<- host SS MC ->- host or other peripherals (optional) </verbatim> A high-to-low transition on the _CS_ pin is required to start an operation and a low-to-high transition is required to end an operation. _Invalid Opcode_: If an invalid opcode is received, no data will be shifted into AT25M02 and the Serial Data Output (SO) pin will remain in a high impedance state until the falling edge of CS is detected again. This will reinitialize the serial communication. While in _Hold_ mode, the SO pin will be in a high impedance state. In addition, both the SI pin and the SCK pin will be ignored. From 1024 Kibit up there are 24 address bits, 8 Kibit to 512 Kibit have 16 address bits. 1, 2, and 4 Kibit have 8 bit address bits. !25LCxxxx Instruction Set | *Name* | *Format* | *Description* | | _READ_ | 0000 0011 | Read data from memory array beginning at selected address | | _WRITE_ | 0000 0010 | Write data to memory array beginning at selected address | | _WREN_ | 0000 0110 | Set the write enable latch (enable write operations) | | _WRDI_ | 0000 0100 | Reset the write enable latch (disable write operations) | | _RDSR_ | 0000 0101 | Read STATUS register | | _WRSR_ | 0000 0001 | Write STATUS register | | PE | 0100 0010 | Page Erase erase one page in memory array | | SE | 1101 1000 | Sector Erase erase one sector in memory array | | CE | 1100 0111 | Chip Erase erase all sectors in memory array | | RDID | 1010 1011 | Release from Deep power-down and read electronic signature | | DPD | 1011 1001 | Deep Power-Dow | !AT25M02 Instruction Set | *Name* | *Format* | *Description* | | _READ_ | 0000 0011 | Read from Memory Array | | _WRITE_ | 0000 0010 | Write to Memory Array | | _WREN_ | 0000 0110 | Set Write Enable Latch (WEL) | | _WRDI_ | 0000 0100 | Reset Write Enable Latch (WEL) | | _RDSR_ | 0000 0101 | Read Status Register (SR) | | _WRSR_ | 0000 0001 | Write Status Register (SR) | | LPWP | 0000 1000 | Low Power Write Poll | %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" width="992" height="600" title="EEPROM Connected to MC's Centronics Connector (Switches and LEDs)" }% ---+ EEPROM Connected to MC's Centronics Connector (Switches and LEDs) Sharing the LED and Switch port, you loose three LEDs and one switch or IN. Possible conflict with the bootstrap loader, if there is a read sequence (CS and read pattern 0000 0011). To prevent this, set the EEPROM into HOLD state e.g. with the <SPAN STYLE="text-decoration:overline">WAIT</SPAN> signal. | *SPI* | *MC (Master)* | *25LCxxxx (Slave)* | *Interface* | | MISO | J2.1 <SPAN STYLE="text-decoration:overline">IN</SPAN> EF4 | 2 SO | diode e.g. 1N4148 | | MOSI | J2.11 O7 LED7 | 5 SI | direct | | CLK | J2.10 O6 LED6 | 6 SCK | direct | | CS | J2.12 O5 LED5 | 1 <SPAN STYLE="text-decoration:overline">CS</SPAN> | direct | | | P4.3 VDD | 8 VCC | +5V capacitor 100 nF to GND | | | " | 3 <SPAN STYLE="text-decoration:overline">WP</SPAN> | +5V | | | J2.14 <SPAN STYLE="text-decoration:overline">WAIT</SPAN> | 7 <SPAN STYLE="text-decoration:overline">HOLD</SPAN> | direct | | | 21 GND | 4 GND | GND | %IMAGE{"%PUBURLPATH%/Cosmac/McForth/mc-eeprom-conn.png" type="thumb" caption="Schematic"}% Raspberry Pi can emulate SPI EEPROM. On RaspiElf the switches/LEDs are already connected to Raspi's GPIOs. No need for additional hardware. But I have to write an SPI server for the Raspberry Pi. Raspi's SPI interfaces can't be used because of conflicting port usage. ---++ Read Byte <pre> CS0 EQU 0b1101111 CS1 EQU 0b0010000 CLK0 EQU 0b1011111 CLK1 EQU 0b0100000 DATA0 EQU 0b0111111 DATA1 EQU 0b1000000 ; MSB first READBYTE: LDI 0 PLO R5 LDI 0xFF PHI R6 LDI 0xFF - 8 PLO R6 SEX R0 BITLOOP: OUT4,0b01000000 ; CLK for SPI OUT4,0b00000000 INC R6 GHI R6 ; set CARRY SHRC GLO R5 B4 SETBIT ; branch if bit set SHL ; bit not set BR SAVEBIT SETBIT: SHLC SAVEBIT: PLO R5 GLO R6 BNZ BITLOOP </pre> about 230 cycles for one byte -> 1 ms -> 1 KiB takes about 1 s @ 1.79 MHz ---++ Write Byte <pre> WRITEBYTE: LDI 0 PHI R6 LDI 8 PLO R6 SEX R0 BITLOOP: GLO R5 ; get the next bit SHLC , next bit is in the carry PLO R5 BDF SETBIT OUT4,0b01000000 ; CLK for SPI with data bit cleared OUT4,0b00000000 BR NEXT SETBIT: OUT4,0b11000000 ; CLK for SPI with data bit set OUT4,0b10000000 NEXT: DEC R6 GLO R6 BNZ BITLOOP </pre> %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" width="992" height="600" title="EEPROM patched on MC PCB" }% ---+ EEPROM patched on MC PCB SPI Mode 0, data is always latched in on the rising edge of SCK and always output on the falling edge of SCK. For CS one output port bis is needed e.g. O7 or N2 (INP4) to start/end operation (A high-to-low transition on the _CS_ pin is required to start an operation and a low-to-high transition is required to end an operation). | *SPI* | *MC (Master)* | *25LCxxxx (Slave)* | *Interface* | | MISO | <SPAN STYLE="text-decoration:overline">EF2</SPAN> | 2 SO | direct | | MOSI | D0 | 5 SI | direct | | CLK | TPB & N1 (OUT2) | 6 SCK | [[https://en.wikipedia.org/wiki/Wired_logic_connection][wired AND]]; Pullup 10 k, 2 1N4148 | | CS | N2 | 1 <SPAN STYLE="text-decoration:overline">CS</SPAN> | direct | | | | 8 VCC | +5V | | | | 3 <SPAN STYLE="text-decoration:overline">WP</SPAN> | +5V | | | J2.14 <SPAN STYLE="text-decoration:overline">WAIT</SPAN> | 7 <SPAN STYLE="text-decoration:overline">HOLD</SPAN> | direct | | | | 4 GND | GND | %IMAGE{"%PUBURLPATH%/Cosmac/McForth/mc-eeprom-u1.png" type="thumb" caption="Schematic"}% ---++ Read Byte <pre> ; MSB first LDI 0 PLO R5 LDI 0xFF PHI R6 LDI 0xFF - 8 PLO R6 SEX R6 BITLOOP: OUT2 ; CLK for SPI, INC Rx GHI R6 ; set CARRY SHRC GLO R5 B2 SETBIT ; branch if bit set SHL ; bit not set BR SAVEBIT SETBIT: SHLC SAVEBIT: PLO R5 GLO R6 BNZ BITLOOP </pre> about 200 cycles for one byte -> 1 ms -> 1 KiB takes about 1 s ---++ Write Byte <pre> WRITEBYTE: LDI 0 PHI R6 LDI 8 PLO R6 SEX R0 BITLOOP: GLO R5 ; get the next bit SHLC , next bit is in the carry PLO R5 LSNF OUT2,0b00000000 ; CLK for SPI with data bit cleared LSDF OUT2,0b00000001 ; CLK for SPI with data bit set DEC R6 GLO R6 BNZ BITLOOP </pre> %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" width="992" height="600" title="EEPROM Connected to Raspberry Pi" }% ---+ EEPROM Connected to Raspberry Pi * http://www.netzmafia.de/skripten/hardware/RasPi/RasPi_SPI.html * https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md * http://wiringpi.com/reference/spi-library/ | *SPI Function* | *BCM/GPIO* | *RaspiElf* | | _SPI0 MISO_ | 9 | IN4 | | _SPI0 MOSI_ | 10 | IN3 | | _SPI0 SCLK_ | 11 | IN6 | | SPI0 CS0 | 8 | IN7 | | _SPI0 CS1_ | 7 | O0 | | EEPROM CS | 5 | O1 | | SPI1 MISO | 19 | O5 | | SPI1 MOSI | 20 | - | | SPI1 SCLK | 21 | shutdown | | SPI1 CS0 | 18 | <SPAN STYLE="text-decoration:overline">CLR</SPAN> | | SPI1 CS1 | 17 | <SPAN STYLE="text-decoration:overline">WAIT</SPAN> | | %IMAGE{"%PUBURLPATH%/Cosmac/MassStorage/raspi-eeprom.png" type="thumb" caption="Schematic"}% | %IMAGE{"%PUBURLPATH%/Cosmac/MassStorage/raspi-zero-eeprom.jpg" type="thumb" caption="Raspberry Pi Zero and EEPROM interface"}% | ---++ eeprom2bin (download tool) $ *NAME*: eeprom2bin - Copies the EEPROM memory to a binary file on the Raspberry Pi. $ *SYNOPSIS*: eeprom2bin [-s hexadr] [-e hexadr] [file] $ *DESCRIPTION*: Copies the EEPROM memory to a binary file (or stdout) on the Raspberry Pi. The Raspberry Pi GPIO SPI0.1 is used as interface to the SPI EEPROM (24 bit address, at least a 1024 Kibit type, 256 byte page). The generated data is written to the standard output stream or to a _file_. Caution: Overwrite file if it exists. Use > for redirecting (save the file) or | for piping to another command (e.g. hexdump). $ *OPTIONS*: Non argument options that are duplicated on the command line are not harmful. For options that require an argument, each duplication will override the previous argument value. $ *-s* _hexadr_: start address in hex (0 is default) $ *-e* _hexadr_: end adress in hex (0x1FFFF is default) ---++ bin2eeprom (upload tool) $ *NAME*: bin2eeprom - Copies the content of binary file on the Raspberry Pi to EEPROM. $ *SYNOPSIS*: bin2eeprom [-s hexadr] [-e hexadr] [file] $ *DESCRIPTION*: Copies the content of binary file on the Raspberry Pi to EEPROM memory. The Raspberry Pi GPIO SPI0.1 is used as interface to the SPI EEPROM (24 bit address, at least a 1024 Kibit type, 256 byte page). Use < for redirecting or | for piping from another command. $ *OPTIONS*: Non argument options that are duplicated on the command line are not harmful. For options that require an argument, each duplication will override the previous argument value. $ *-s* _hexadr_: start address in hex (0 is default) $ *-e* _hexadr_: end adress in hex (0x1FFFF is default) ---++ How to get and build the RaspiElf tools Get the source from the [[https://github.com/spyren/RaspiElf][GIT repository]] (if you have not installed GIT yet, then install it with =sudo apt-get install git=), type only the bold text after the $ sign: <pre> pi@cosmac:~/elf $ <b>git clone https://github.com/spyren/RaspiElf</b> Cloning into 'RaspiElf'... pi@cosmac:~/elf $ </pre> Build (compile) from the sources: <pre> pi@cosmac:~/elf $ <b>cd RaspiElf</b> pi@cosmac:~/elf/RaspiElf $ <b>cd eeprom/</b> pi@cosmac:~/elf/RaspiElf/eeprom $ <b>make</b> cc -g -c eeprom2bin.c cc -g -o eeprom2bin -lwiringPi eeprom2bin.o cc -g -c bin2eeprom.c cc -g -o bin2eeprom -lwiringPi bin2eeprom.o pi@cosmac:~/elf/RaspiElf/eeprom $ </pre> Install the binaries into =/usr/local/bin= <pre> pi@cosmac:~/elf/RaspiElf/eeprom $ <b>sudo make install</b> install -m 557 eeprom2bin bin2eeprom /usr/local/bin </pre> Install !wiringPi (GPIO Interface library for the Raspberry Pi), details see http://wiringpi.com/download-and-install/ Enable the SPI interface <pre> @cosmac:~/elf/RaspiElf/eeprom $ <b>sudo raspi-config</b> </pre> * 5 Interfacing Options Configure connections to peripherals * P4 SPI Enable/Disable automatic loading of SPI kernel module %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="box_start" width="992" height="600" title="Kermit/ZModem" }% ---+ Kermit/ZModem What about using KERMIT or ZMODEM protocol for the file transfer and use the file system on the host? No need to add additional hardware (SD-card is anyway to modern ;-) You could use an old CP/M or even a PDP11 as host. The C-Kermit Local Server mode, e.g. MC can read/write the blocks as files =block.0=, =block.2=, =block.255=. The serial communication is really slow, not only because of the 9600 baud, but you have to wait after each character to give CDP1802 some computation time. https://github.com/utoh/pygmy-forth/blob/master/extras/kermit/pfkerm.doc %DASHBOARD{ section="box_end" }% %DASHBOARD{ section="dashboard_end" }% -- %USERSIG{PeterSchmid - 2019-01-24}% ---++ Comments %COMMENT%
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