Re: gEDA-user: wont be watching list :(

[DJ Delorie <dj@xxxxxxxxxxx>]

> 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.