This might throw a spanner into your works
at this last stage of design but why do you not use the 2129 part as it has ADC
built in with lot's of IO and you need no multipexing here!
----- Original Message -----From: J.C. WrenSent: Saturday, February 07, 2004 9:27 PMSubject: [lpc2100] Evalulation Card UpdateI've got an overview of what I'm thinking of going with for the
evaluation card. < http://tinymicros.com/embedded/LPC210x >
Basic goals: Have several of each bus type supported, i.e., several SPI
peripherials, several I2C, and several 1-wire. Try to make devices
generally useful.
All devices are 3.3V. All devices can be disconnected from Vcc and
their respective control signals via jumpers (can you say :lots of
jumpers"?). In addition to the two JTAG interfaces being available, a
Wiggler type interface is built-in. Also the "hands-off" ISP
programming mode is supported.
One DB-9 for serial port 0 (2 lines), one DB-9 for serial port 1 (with
all 8 control signals).
Where signals conflict, jumpers will allow selecting the use of one set
or the alternate set. All I/Os are available on 2 headers. By removing
the device jumpers, the LPC210x can be completely unperipherialed. By
removing the device Vcc jumpers, one should be able to measure currents
for a given configuration, such as "how much current will just the
LPC2106 + SD card pull?".
Reasonable power supply for on-board devices, plus a fair chunk of
capacity for users circuity. I'm considering either putting jumpers on
the 3 Vcc rails, or 1 ohm resistors, for current measurement. Also
including several points to attach a 'scope ground (likely pads for a .1
or .2 inch wire loop).
There will probably be no prototype area. However, the I/O connectors
will be arranged so that the user can plug in a card on Vector board on
.1 centers, and be able to get power, I/O, and control signals.
Prototyping area costs real money, and I personally hate defacing
boards. If there's enough feedback, I'll add it on. Please specify how
much area you'd want, to .1 inch resolution.
The SD/MMC card connector will support the physical SD card. I had
planned on only supporting the SPI mode, but there's several uncommitted
I/O lines on the processor, so I may wire those up (with jumpers, of
course) to support SD mode.
The A/D is an 8 channel 10 bit part. One of the MCP23016 I/O expanders
will have 8 LEDS and 8 switches (drawing shows pushy buttons, they'll
actually be rockers). The other MCP23016 pins will be available on a
2x10 header. NVRAM shown is a Ramtrom FRAM, any 24CL64 device should
work (pin outs are the same). RTC will have a battery (not shown),
diode OR'ed in with Vcc. DS2405 1-wire switch has LED to indicate
state. I2C devices with interrupt lines will be jumperable to EINT0,
EINT1 or EINT2.
I think that's everything. I'll be doing schematics over the weekend,
most likely. If you have any ideas, I'd love to hear them.
--jc