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Advertising Index Altronics.................................35-38 Blackmagic Design....................... 7 Dave Thompson........................ 111 DigiKey Electronics....................... 3 Emona Instruments.................. IBC Hare & Forbes............................... 9 Jaycar............................. IFC, 59-62 Keith Rippon Kit Assembly....... 111 Lazer Security........................... 111 LD Electronics........................... 111 LEDsales................................... 111 Microchip Technology.............OBC Mouser Electronics....................... 4 PMD Way................................... 111 SC Ideal Bridge Rectifiers......... 108 Silicon Chip Back Issues......... 103 Silicon Chip Binders................ 111 Silicon Chip PDFs on USB......... 80 Silicon Chip Shop...................... 95 Silicon Chip Subscriptions........ 81 TME............................................. 11 The Loudspeaker Kit.com.......... 10 Wagner Electronics....................... 8 Notes and Errata Automatic LQ Meter, July 2024: a few constructors had problems with IC1 (OPA2677) oscillating, making it hot and causing excessive current to be drawn from the battery. Some have solved it by replacing diodes D1 & D2 with some from a different batch or by adding a 220Ω resistor in series with diode D1 (see Mailbag, September 2024, page 10). A better solution is to replace IC1 with an OPA2890 op amp. If you bought a kit and have this problem, contact us to request an OPA2890. Next Issue: the November 2024 issue is due on sale in newsagents by Monday, October 28th. Expect postal delivery of subscription copies in Australia between October 25th and November 13th. 112 Silicon Chip Clock (December 2015 & January 2016; siliconchip.au/Series/294) and set up MPLAB X v5.50 and the current XC32 compiler. It appears that Microchip no longer includes the plib.h, math.h and string.h headers with the compiler. Can you tell me what version of MPLAB and the XC32 compiler you used when you developed the clock? The code is in a folder called LED Clock.X, which suggests that the IDE was some version of MPLAB X. Starting with v5.35, it wanted to upgrade the file, so I worked backwards to v4.20 which didn’t. Having found those headers, I got a heap of other errors when I tried to compile the code. I think it might be better if I use the same version of the software you did originally. Some lines in the code that are particular problems are calls to assembler instructions such as: asm volatile (“eret”); There is a similar line with the “wait” instruction. Do I have to do something in Project Properties to get these lines to compile/assemble? The error message is: “C:\Program Files (x86)\ Microchip\xc32\v1.31\bin\ xc32-gcc.exe” -x c -c -mprocessor=32MX170F256B -ffunction-sections -mips16 -Os -fomit-frame-pointer -DSHOW_UTC_FEATURE=1 -MMD -MF build/default/production/ sleep.o.d -o build/default/ production/sleep.o sleep.c -DXPRJ_default=default -legacy-libc -mno-float -G2048 C:\Users\Gjc\AppData\Local\ Temp\cciHwjKm.s:133: Error: unrecognised opcode `wait’ (G. C., Mount Dandenong, Vic) ● You are right that they are no longer packaging those older libraries with XC32. This page on the Microchip website explains where to get plib.h and the other headers: siliconchip.au/ link/abyw It is now a separate download on the same page where you get the compiler. “math.h” and “string.h” are part of the standard C library, so we are surprised they are not included with the compiler. The above download may include them as well. The build logs in the software download package show that the Australia's electronics magazine compiler used was XC32 v1.31. It should be possible to get it to compile with the latest XC32 with some fiddling (basically downloading and installing headers), but you are right that it might be easier to go back to that earlier version. We wonder if the “unrecognised opcode” error is related to the -mips16 option. We suggest you try switching off the MIPS16 option for that file; you can do it in the IDE on a file-byfile basis. MIPS16 is a more compact instruction set, and we used it because the code wouldn’t fit into the available flash memory otherwise. However, it doesn’t seem to include the wait or eret instructions; those appear to be part of MIPS32 only. We suspect the compiler used to detect that and switch to MIPS32 mode to execute those instructions, but it may no longer do that. The strange thing is that the code obviously compiled for us back in 2015, even though we were using the same version of XC32 (v1.31) as you. Perhaps it has something to do with the IDE providing the compiler with a different set of option flags. Without the MIPS16 flag, the compiled objects will likely be a little larger, but we don’t think they all need to be MIPS16 for the software to fit in the chip. So you might be able to get away with switching just those problem files back to MIPS32 mode. Information wanted on EA project I am looking for the original article for the Xenon Strobe Timing Light project that used a Dolphin torch for the reflector and housing. I built one when I was younger. It was published approximately between 1980 and 1982; I seem to remember it was either in the Electronics Australia or ETI magazine. Looking through EA issues between 1979 and 1982, I found the Digital Tacho/Dwell meter and the Transistor-­ Assisted Ignition projects that I built around the same time, but not the Strobe. (S. R., via email) ● The only project we can find in EA or ETI that used a Xenon flash tube in a Dolphin torch reflector is the Digital Strobe project in EA, March 1986 (starting on page 42). However, it is a strobe and not a timing light, as it isn’t triggered by an ignition system. SC siliconchip.com.au