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20b:software-flash_4_banger [2008/07/30 22:20]
newell created
20b:software-flash_4_banger [2008/07/30 22:23] (current)
newell Uploaded binary file.
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 +{{:​20b:​flash_4_banger.tgz|}}===== RPN hex 4 banger =====
 +
 +==== Description ====
 +
 +A flash resident(!) sample program, this time a dirt-simple 4 function hex calculator (32 bit ints only).
 +
 +==== Usage ====
 +
 +Use SAM-BA or any other comfortable flash programming tool to install the .bin file.  It's less than
 +3kB.  Of course, you will lose any existing firmware in your HP-20B, so be sure you backup the stock
 +HP firmware before erasing it.
 +
 +Expect RAM to be corrupted if you decide to reload the stock HP firmware.
 +
 +Install this firmware at your own risk.
 +
 +==== Download link ====
 +
 + ​{{20B:​flash_4_banger.tgz}}
 +
 +==== Readme.txt ====
 +
 +Another basic sample program for the HP20B. ​ This time it's a four
 +banger 32 bit hex calculator. ​ I think it's RPN, but it may not be
 +exactly correct...
 +
 +Use the top row (N -> Amort) for the A -> F hex digits.
 +
 +Active keys include "​("​ (roll down), "​Input"​ (enter), "​+/​-"​ (chs), "​CE"​
 +(ce), "<​-"​ (backspace/​ce),​ and the four functions. ​ Oh, the shift key 
 +now works. ​ The only shifted function is off, which is shift+on.
 +
 +The "​Input"​ LCD annunciator will be active when an unterminated value is
 +present in the X register. ​ (The RPN annuciator comes on at boot to show
 +that the program is running.)
 +
 +The scancode of the last keypress is shown in the exponent area of the
 +LCD.
 +
 +Runs from flash, Thumb mode, trashes memory, and requires some sort of
 +flash programming tool to install.
 +
 +There'​s no keypad debouncing--the code simply waits for the key to be
 +released. ​ I'm sure that spinlock is very coin cell friendly. ​ I 
 +measured less than 100nA (very hard to measure, my Tek TX3 current meter is too noisy
 +for a clean measurement) in off mode, and about 2mA while running. ​ There
 +is no power management at all--no sleep mode, no halts, no interrupts, and no
 +auto off timer.
 +
 +I'll add source as soon as I've had a chance to double check and
 +add some comments.
 +
 +Disclaimer: Yes, the code is ugly.  Fix it at your own risk.  Consider
 +it nothing more than a toy to demonstrate that we know a little about
 +the hardware.
 +
 +Happy HP Hacking!
  
20b/software-flash_4_banger.txt · Last modified: 2008/07/30 22:23 by newell