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| -rw-r--r-- | avr/main.c | 48 |
1 files changed, 48 insertions, 0 deletions
@@ -22,6 +22,54 @@ (Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH) */ + +/* this project is designed for the USB AVR LAB board by ullihome + * (http://www.ullihome.de/wiki/USBAVRLab/index) + * That's a small Atmega8-powered board with software-USB and a small pinout + * that looks like this: + * ____ ____ ____ ____ + * | . . . . . | | o . . . . | + * | . . . . . | or | x . . . . | + * |___________| |___________| + * + * hold the DS1992 token against the pins, so that the outer ring touches the + * "x" pin, while the inner circle touches the "o" pin. + * + * How to use: + * the dumping device has three modes of operation, which are shown by the blinking + * speed of the blue LED. + * 1. reading mode: normal blinking + * 2. reading mode: slooow blinking (previous operation failed) + * 3. writing mode: fast blinking + * + * in either mode, the red LED flashes periodically. This means that the device + * probed for a DS1992, but couldn't find anything on the bus. If you hold you + * DS1992 against the pins, the flashing will turn green instead. This means that + * the token has been read into the device's RAM. + * You can now use `pc/a.out read` to read the contents. + * (If both green and red leds flash, this means you've a short circuit.) + * + * If you execute `pc/a.out write <page> <data>`, then the device will enter + * writing mode. The flashing red LED has the same meaning as before. If you now + * connect the token, the page <page> (1-indexed) will be written to with <data>, + * whenever the LED flashes green the next time. + * After that, the device enters reading mode again. If the LED blinks really slow, + * then there was a write error. re-execute a.out write, reconnect the token and retry. + * Additionally, after writing you can use `a.out read` again (without connecting the + * token for reading previously). This will output you a lot of garbage, but the first + * byte read tells you a more detailed error code: + * 0x01: "reset/presence pulse" failed after scratchpad write + * 0x02: scratchpad did not verify correctly + * 0x03: "reset/presence pulse" failed after scratchpad readback + verify + * 0xFF: probably successful + * + * Note that you should read back the data after writing, just to be sure. + * Also note that while you can read the whole memory at once, you must execute the write + * command, and also connect the token, four times for a full write (once for each page). + */ + + + #include <avr/io.h> #include <avr/interrupt.h> #include <avr/wdt.h> |