+InsaneMultitasker Posted August 6, 2018 Share Posted August 6, 2018 Does anyone here have experience with 2-wire serial EPROMs? I'm looking for one that could easily interface with the 9901. While I could probably squeak by with 128 bytes, I would certainly not be opposed to larger sizes up to 256K. What I'd like to do is connect the clock and serial data pins to the 9901, using two unused pins. I'd then use the serial eeprom to store configuration information for the Geneve and its devices. 20-odd years ago Jim S. had interfaced a serial eprom to the Geneve to provide Cecure a hardware-based copy protection. Thus I know a 2-wire device can be implemented, I just don't know what is available today that might work well for this application. 1 Quote Link to comment Share on other sites More sharing options...
Stuart Posted August 6, 2018 Share Posted August 6, 2018 (edited) If you're talking about an I2C EEPROM, you can implement an I2C interface easily on a 9901 - I done one using the joystick port. http://www.stuartconner.me.uk/ti/ti.htm#i2c_interface https://learn.sparkfun.com/tutorials/reading-and-writing-serial-eeproms Edit: Ideally you'll need *three* unused pins on the 9901 to implement an I2C interface: one to drive the clock, one to output data, and another to input data - because once you programme a pin on the 9901 as an output, you can't use it again as an input unless you do a hard or soft reset of the 9901. You might be able to get away with doing a soft reset at the point where you want to switch between reading and writing the interface, depending on what happens to the clock output at the point you do the reset (will it float high or low, and what does the I2C interface expect on the clock output at that point?), and what other things are connected to the 9901. Edited August 6, 2018 by Stuart 1 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted August 7, 2018 Author Share Posted August 7, 2018 Thanks, Stuart, I'll take a closer look at your site. Here is one of the snips of code I came across. The routine appears to use three CRU bits. I cannot find any records that indicate which chip was used back then, but the concept seems to be similar to what you describe. Knowing the I2C interface works well is already one step ahead of where I was the other day DEF UPROG,SFIRST,SLOAD,SLAST HIWS EQU >F000 my hi workspace DXOP CALL,0 define CALL as meaning XOP 0 SK EQU 19 CS EQU 21 IN EQU 24 OUT EQU 24 * * preliminaries; request memory, fetch argument line etc * SFIRST SLOAD UPROG LWPI HIWS use a fast workspace LIMI 0 CLR R12 LI R1,>1200 MOVB R1,@>F112 RDPROM CLR R8 LI R10,BUFFER LI R9,BUFF2 CLR R6 SBO IN LOOP1 SBZ SK SBO CS SBZ SK SBO SK BL @SNDBYT SBO IN LI R12,>0030 STCR R6,1 CLR R12 SBZ SK SBO SK RDLOOP BL @RCVBYT MOV R6,*R10+ MOV R6,*R9+ SBZ CS INC R8 CI R8,63 JNE LOOP1 SBZ SK BL @TTYOUT DATA BUFF0 BLWP @0 SNDBYT MOV R8,R3 AI R3,>0080 LI R2,8 SRC R3,15 SLOOP LI R12,>0030 LDCR R3,1 MOVB R3,*R9+ SRC R3,15 CLR R12 SBZ SK SBO SK DEC R2 JNE SLOOP RT RCVBYT LI R2,16 CLR R6 RLOOP CLR R5 SLA R6,1 SBZ SK SBO SK LI R12,>0030 STCR R5,1 SWPB R5 A R5,R6 CLR R12 DEC R2 JNE RLOOP SRL R6,1 SWPB R6 RT TTYOUT LI R0,>27 LI R1,HIWS+8 MSB R4 LI R2,1 MOV *R11+,R3 STRING ADDRESS TTY1 MOVB *R3+,R4 GET NEXT CHAR JEQ TTY2 IF DONE CALL @VIDEO JMP TTY1 TTY2 RT * * MDOS SYSTEM CALL PARAMETERS * BUFF0 BYTE 12,10 BUFFER BSS 126 BYTE 10,10,10,13,0 BUFF2 EQU >4000 * 0 1 0 0 0 0 KEY DATA 5 keyscan xop VIDEO DATA 6 video xop MEM DATA 7 memory manager xop DSK DATA 8 i/o xop UTL DATA 9 utility xop SLAST DATA 0 END Quote Link to comment Share on other sites More sharing options...
Willsy Posted August 7, 2018 Share Posted August 7, 2018 I'm using FRAM in my designs at work. I've stopped bothering with Flash completely. Some devices: Fujitsu MB85RC256V - 32x8 bit I2C FRAM - 2.0 V to 3.6 V Fujitsu MB85RC128 - 16kx8 bit I2C FRAM - 2.7 V to 3.6 V Cypress FM24V10 - 1-Mbit 128K × 8 Serial I2C F-RAM - 2.7 V to 5.5 V FRAM (a Texas Instruments invention) has considerable advantages over Flash memory: High-endurance 100 trillion (10 ) read/writes 151-year data retention No-Delay writes Advanced high-reliability ferroelectric process No complex page setup/incantations to write to memory - for reads and writes, the devices are addressable at the byte level; there's no page-level wear-management issues to worry about All of the above devices at simple 8-pin devices. They are surface mount but there are little adaptor boards available if you want to use 2.54mm DIL. Data sheets attached. Have fun :-) FM24V10 128Kx8 I2C FRAM Datasheet.pdf Fujitsu-MB85RC128PNF-G-JNE1-datasheet.pdf MB85RC256V.pdf 6 Quote Link to comment Share on other sites More sharing options...
+FarmerPotato Posted August 7, 2018 Share Posted August 7, 2018 I've been a fan of FRAM ever since I wandered by the lab door of RamTron at UCCS. Texas Instruments has licensed it and brought it into the mainstream after 30 years. Here is a neat TI LaunchPad board with '430 CPU with on-chip FRAM that can run several flavors of FORTH. It often goes on sale for $4.30 http://www.ti.com/tool/MSP-EXP430FR2433 1 Quote Link to comment Share on other sites More sharing options...
+TheBF Posted August 8, 2018 Share Posted August 8, 2018 I'm using FRAM in my designs at work. I've stopped bothering with Flash completely. Some devices: Fujitsu MB85RC256V - 32x8 bit I2C FRAM - 2.0 V to 3.6 V Fujitsu MB85RC128 - 16kx8 bit I2C FRAM - 2.7 V to 3.6 V Cypress FM24V10 - 1-Mbit 128K × 8 Serial I2C F-RAM - 2.7 V to 5.5 V FRAM (a Texas Instruments invention) has considerable advantages over Flash memory: High-endurance 100 trillion (10 ) read/writes 151-year data retention No-Delay writes Advanced high-reliability ferroelectric process No complex page setup/incantations to write to memory - for reads and writes, the devices are addressable at the byte level; there's no page-level wear-management issues to worry about All of the above devices at simple 8-pin devices. They are surface mount but there are little adaptor boards available if you want to use 2.54mm DIL. Data sheets attached. Have fun :-) FM24V10 128Kx8 I2C FRAM Datasheet.pdf Fujitsu-MB85RC128PNF-G-JNE1-datasheet.pdf MB85RC256V.pdf These are new to me, being out of the industry for 20 years. Do you use these like disk and read the data into RAM at startup? Does anybody make them with address/data buss access like static RAM? (maybe not needed, if they are fast enough using serial) B Quote Link to comment Share on other sites More sharing options...
RickyDean Posted August 8, 2018 Share Posted August 8, 2018 These are new to me, being out of the industry for 20 years. Do you use these like disk and read the data into RAM at startup? Does anybody make them with address/data buss access like static RAM? (maybe not needed, if they are fast enough using serial) B Sounds like a new version of SAMS to me. Quote Link to comment Share on other sites More sharing options...
Willsy Posted August 8, 2018 Share Posted August 8, 2018 These are new to me, being out of the industry for 20 years. Do you use these like disk and read the data into RAM at startup? Does anybody make them with address/data buss access like static RAM? (maybe not needed, if they are fast enough using serial) No, you literally use them as RAM. Read/Write from/to them as you want with impunity. The only difference is they are serial devices (I haven't seen one with a parallel address/data bus). When the power goes off they retain their contents, unlike traditional ram. The "F" in FRAM refers to "ferro". Remember those old magnetic core, or "bubble" memories? The FRAM is based on the same technology, just scaled right down to the micron level. Incredible. You can't get anything like the density of modern DDR type "computer" memory. The biggest I've seen is 128KB, but for embedded projects that's perfect. Flash is a major pain the a$$ to work with. 1 Quote Link to comment Share on other sites More sharing options...
Willsy Posted August 8, 2018 Share Posted August 8, 2018 I spoke too soon... Fujitsu now have a part with a "traditional" parallel address/data bus and 4mbit capacity. Neat. 3 Quote Link to comment Share on other sites More sharing options...
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