The Marshall Valvestate AVT 2000 – AVT Stage Foot Controller (it doesn’t seem to have a short codename as far as I can tell) is, as its name suggests, a foot controller for some of Marshall’s Valvestate series amps. It has 6 buttons (4 momentary, 2 toggle) and 6 LEDs. Connection to the amp is by way of a 15 pin D-sub connector.

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I scored a few DMF-50573NB-FW 480×80 pixel graphic LCDs off trademe for $NZ5 each. However, the documentation around on the internets for this particular variant of the Optrex DMF family seems to be sparse. So here is the information that I have gleaned from the looking at the devices themselves, datasheets for other LCDs in the family, probing with a multimeter and general experimentation. No guarantees as to the accuracy of this data, but so far it has worked for me. If anyone has a datasheet please link in the comments .

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While working on my control 16 project I realised I would need to replace the firware of the onboard microcontroller, an AT89C52. Unfortunately, the AT89C52 is a mission to program (as it is parallel programmable only) so I have replaced it with an AT89S52, which supports in-circuit serial programming. What I still lacked was an ISP programmer; however, instead of building one I made use of an old Xilinx DLC5 parallel port JTAG cable (schematic). This was fairly straight forward under Ubuntu 9.04, using UISP AVR and AT89S programming software. The following instructions assume the target is self powered and has an oscillator/crystal connected if required. NB these instructions are written from memory, so if you find a mistake please post a comment.

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