> Could you give me some more info on these Renesas chips? http://america.renesas.com/ -> MPU & MCU -> M16C Family Catalog (or scroll down and click on the "M16C Family" header)
The R8C/M16C families are very similar software-wise (16 bit registers, 16 bit default pointer, 1Mb address space) but offer a wide range of hardware, from tiny 20 pin chips (the R8C/17 is 6.4 x 4.3 mm 0.65mm pitch) to big 128 pin ones. The M32C families have 16 bit data registers and 24 bit default pointers, faster clocks, and a 16Mb address space, in 100-144 pin versions. All the chips are fine pitch SMT (no bga or dip). They all have the usual collection of embedded hardware goodies, of course. > What kind of programmer do you use, whats your development IDE, flow > like? The eval boards come with either USB or RS232 cables that plug into a standard 10 pin 100 mil header. There's a simple serial protocol to program them. Actually, there are two - one for raw programming, and one that works with their on-chip debugger software. Basically, though, you only need a few connections to the chip - rx/tx serial and reset - to add a programmer port to it. Their docs even provide sample schematics. I've hacked one of my cables to use DTR to reset the board via a mosfet. This is convenient because not only can software control it, but normally the board auto-resets when you exit the downloader (my downloader continues monitoring the serial port after download, so you can use it as stdout and send an exit code ;) I use emacs, gcc, and gas with standard C programs. You compile them to SREC and download them, either with their tools (Windows) or a downloader I wrote (linux) for their on-chip debugger. We have a simulator too, but it's still being reviewed for FSF inclusion. > I am interested in development with GCC. I guess redhat released a > port for these chips? Yes, I wrote the gcc and newlib parts and the simulator, Stan Cox wrote the binutils part, and Jim Blandy wrote the gdb parts. The target is m32c-elf. > Also when you say one-wire do you mean Dallas one-wire bus? Yes. I use the sample thermo/humidity module built off their battery monitor chip, plus four silicon serial numbers to sense the pushbuttons. There's a bunch of mosfets on the furnace board to multiplex them all together. There are four wires running to each thermostat - power, ground, lcd serial, and onewire.
