cerickson wrote:Are there any changes to the Arduino Mega 2560 board that are required to convert it to Zbasic?
No modifications to the board itself are required but you may need to or want to change the "fuse" settings. See
AN-103 - Preparing ZBasic Generic Target Devices for more details. If you're going to use a ZBasic-compatible bootloader (see discussion further below), I would recommend these fuse settings: ext=0xfd, hi=0xd6, lo=0xd7. If you're going to program your app into the device using an ISP, the Arduino Mega 2560 fuse settings of ext=0xfd, hi=0xd8, lo=0xff are probably fine.
cerickson wrote:Are there any special compiler directives required to run Zbasic on the Arduino Mega 2560?
Yes. From the perspective of ZBasic, the Arduino Mega 2560 is just a generic ATmega2560 so the information in
Chapter 5 of the ZBasic Language Reference Manual applies.
In particular, you need to specify several device parameters. Most of them derive from the main clock frequency - 16MHz on the Arduino Mega 2560. The set of device parameters below will probably work fine, just add them to the top of the primary .bas file (the one with the Main() in it). You can also specify device parameters in the .pjt file but the form is slightly different (see the discussion of the --device-parameter option).
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Option DeviceParameter package "TQFP-100"
Option DeviceParameter clockFrequency 16000000
Option DeviceParameter rtcFrequency 500
Option DeviceParameter rtcScale 1
Option DeviceParameter swUartDivisor 8
Option DeviceParameter swUartMinSpeed 300
Option DeviceParameter swUartMaxSpeed 19200
Option DeviceParameter swUartBaseSpeed 2400
Option DeviceParameter timerSpeed1Divisor 1
Option DeviceParameter timerSpeed2Divisor 8
This set of device parameters was generated using the "Target Options" dialog, available via the Options|Target Options menu item
after you've selected the target generic device. See
Section 9.6 Setting Target Options for more information.
cerickson wrote:Are there any special limitations or considerations involved with running Zbasic on an Arduino Mega 2560?
The only limitations are those imposed by the device itself and its main clock frequency.
There is a question of how you're going to get the application code into the Arduino Mega 2560 device. One option is to use an AVR-compatible In-System-Programmer (ISP) device like the Atmel ATAVRISP2 (unfortunately, no longer manufactured) or equivalent. You can also use another Arduino with a special AVR ISP sketch to program AVR devices. A Google search with suitable keywords will return useful links.
Another alternative is to first install a ZBasic compatible bootloader. Source code and a build script for such a bootloader is provided in the zboot directory of the ZBasic installation directory. Of course, you need an ISP device to put the bootloader on the AVR (see the preceding paragraph) but after that you can download your application to the device in a manner similar to that used for ZX devices. If you do install a ZBasic-compatible bootloader you'll need one additional device parameter:
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Option DeviceParameter ZBasicBootloader true
