Thursday, September 29, 2016

Keypad print string command

( Warning this is an early examination and interpretation of the data, some of the deductions I made are not accurate)
This is the first of a series of posts, where I'll try examine the list of commands I logged from a dialogue between the keypad and the mainboard.

Here the first: Print on display

A stream starting with the byte 0x13 seems to have the means of "print command".
This command seems to have a fixed length of 21 bytes.

Command example:
The following sequence prints on screen starting on top left: “Hello world!”

0x13 print command
0x10 address of the first keyboard on the bus.
0x14 Unknown at the moment, but it must be present
0x00 the position 0x00 on the display, which means corner top – left
0x48,0x65,..,0x64,0x21,0x20,0x20,0x20,0x20 “Hello world!    ” 
0x06 checksum: 10+14+00+48+65+6c+6c+6f+20+77+6f+72+6c+64+21+20+20+20+20=>0501=>05+01=06

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