note on V1.0 vs. V1.2

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Romain Dolbeau 2022-11-18 17:47:03 +01:00
parent 3434158dab
commit 62f01c463b
1 changed files with 3 additions and 0 deletions

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@ -22,6 +22,9 @@ Directory 'nubus-to-ztex'
The V1.0 custom board is a NuBus-compliant (I hope...) board, designed to receive a [ZTex USB-FPGA Module 2.13](https://www.ztex.de/usb-fpga-2/usb-fpga-2.13.e.html) as a daughterboard. The ZTex module contains the actual FPGA (Artix-7), some RAM, programming hardware, etc. The NuBus board contains level-shifters & drivers ICs to interface between the NuBus signals and the FPGA, a CPLD handling some level-shifting & the bus mastering arbitration, a serial header, two user Leds, 14 debug Leds tied to specific NuBus or CPLD/FPGA signals, a JTAG header, a USB micro-B connector, a VGA chip & connector, and a HDMI chip & connector. It supports every NuBus feature except the optional parity (i.e. it can do both slave and master modes).
The V1.0 board is in commit 3f3371a. The CPLD solution works but is annoying as it requires older Xilinx software (ISE 14.7) and dedicated JTAG programmer to use. A revision V1.2 board is in the work but not yet made, which will remove the VGA connector and CPLD (and require more dedicated level-shifters/drivers) and replace them by a micro-sd card slot and an expansion connector (Pmod-like).
The PCB was designed with Kicad 5.0