SmartMedia logging
I've designed SmartMedia
logger for deatached devices which need slow logging for long
time. For example my heating controller
. More than two years of logging ten temperatures every minute is
possible in such way. Logging with speeds up to 19200 baud can be
performed. With higher speeds of crystal or interrupt driven program
hihger speeds are possible.
Features
- SmartMedia cards from 64MB to 128MB
- Atmel AT89C2051 Microcontroller
- 3.3V power supply with small LM317
- Direct connection to 5V or 3V MCU for TX->RX path.
- Pass-through serial ASCII logger software
- Inexpensive 22 pin DIL connector for SmartMedia connection
- PCB size 5 x 3 x 1 cm with SmartMedia card attached
- Logging control with escape sequence commands
- High speed LOG dump - 57600 bps for download to serial terminal
- Keil C source
Schematics
Schematics is designed to be easily built and used by inexpensive
microcontroller such as AT89C2051-24PI which can operate at 3V with
11.094MHz quartz without a problem. Atmel claims that for 3V operation
one should use low speed 89C2051 MCU, but I think that the die is the
same and that 5V device can be used for 3V design as long as the speed
is not compromised.
LED diode monitors SmartMedia activity. Note that /CE and RY/BY
pins are connected together for writing to media and reading busy.
Two additional 10k pullups are erquired as this pins are alacking
internal pullup.
Typically we connect this logger between TX port of host
microcontroller and MAX232 driver. Input resistor on RX pin is for 5V
to 3V level change. MAX232 can be driven with 3V.
Shematics is available in
pdf
or png
or postscript.
Source for gschem is also available
as logger.sch
Source
C source fits into 2K Flash. We control
the logger with host computer via escape AT (@) commands. Erasing,
information, dump of the history is available.
I've assumed that the SmartMedia card is without an error which is
likely. I've verified mine with a simple program checking extra 16byte
area for each block. Consult specs for info.
Hex dump is available for quick startup
PCB
Processor PCB
SmartMedia with 22pin socket attached
Leon Kos
Last modified: Thu Nov 27 13:34:24 CET 2003
