diff --git a/assets/hp-50g.jpg b/assets/hp-50g.jpg new file mode 100644 index 0000000..4a981ef Binary files /dev/null and b/assets/hp-50g.jpg differ diff --git a/know-how/hardware/_posts/2017-03-18-hp-50g.md b/know-how/hardware/_posts/2017-03-18-hp-50g.md new file mode 100644 index 0000000..3c9efcf --- /dev/null +++ b/know-how/hardware/_posts/2017-03-18-hp-50g.md @@ -0,0 +1,21 @@ +--- +title: HP 50g +layout: default +language: en +created: 2017-03-18 16:14:51 +0100 +updated: 2017-03-18 16:14:51 +0100 +toc: false +tags: + - know-how + - hardware + - hp + - 50g + - calculator +--- +![HP 50g]({{ site.url }}/assets/hp-50g.jpg) + + diff --git a/know-how/hardware/hp-50g/_posts/2017-03-18-missed-keypresses.md b/know-how/hardware/hp-50g/_posts/2017-03-18-missed-keypresses.md new file mode 100644 index 0000000..a630d63 --- /dev/null +++ b/know-how/hardware/hp-50g/_posts/2017-03-18-missed-keypresses.md @@ -0,0 +1,57 @@ +--- +title: HP 50g and missed keypresses +layout: default +language: en +created: 2017-03-18 22:29:30 +0100 +updated: 2017-03-18 22:29:30 +0100 +toc: false +tags: + - know-how + - hardware + - hp + - 50g + - calculator +--- +The default key debouncing wait time in the HP 50g is very long so that it misses lots of +keypresses when typing fast. E.g. when typing `500` the calculator only registers `50`. This +behaviour is controlled by the `KEYTIME` setting. + +The `KEYTIME` setting specifies the number of processor ticks, any further keypresses are ignored +after a key was pressed. The default value is **1138** which resembles about 140 ms. + +Setting this to e.g. **500** (~61 ms) makes entering numbers much more reliable. Some users even +disabled it by setting it to **0** and had no problems at all. + + +Changing the value +================== + +To set the `KEYTIME` setting to **500**, press the following keys (in RPN mode): + +1. 500 +1. ENTER +1. ALPHAALPHA +1. KEYTIME +1. STO ▶ + +But this only works for the current session. After a reboot of the device, the value will be back +to the default value of **1138** again. + + +Changing the value on bootup +============================ + +To have this value changed on every bootup of the calculator, we have to save the instructions +to a special variable called `STARTUP`. To do this, press the following keys (in RPN mode): + +1. + (this will insert `<< >>` and place the cursor in the middle) +1. 500 +1. 0 (this will insert a `→`) +1. ALPHAALPHA +1. KEYTIME +1. ENTER +1. STARTUP +1. STO ▶ + +This stores the instruction into the special variable `STARTUP` which gets evaluated on every +bootup.