SerLCD how to write characters from the LCD ROM with values higher than 0x7F

Components & Accessories Displays
1

Hi, I successfully ported a CircuitPython script written for use with a standard Hitachi HD44780 to use with a SparkFun LCD-16398 20x4 RGB backlight Qwiic display. My script decodes and displays GPS datagram messages broadcasted by Microsoft Flightsimulator, via the app FSUIPC7 GPSout2 function (as a kinda middle-man).

I use the character in ROM at address 0xDF to indicate the ‘degrees’ character in Latitude and Longitude position values.

However with the SparkFun SerLCD the character at ROM position 0xC5 is displayed instead. (I use the addresses shown in page 17 of the datasheet of a standard Hitachi HD44780 LCD)

Question: what do I have to change to get the correct character displayed ?

The part of the script that writes the latitude is:

s = “{: >2s}\xDF{:0>2s}'{:0>2s}.{:0>2s}"”.format(lat_v[:2], lat_v[2:4], lat_v[5:7],lat_v[7:])

lcd.write(s)

See the image at: https://imgur.com/zeZPZJ4

Second question: does SparkFun have somewhere in its documentation a datasheet of the LCD used in the LCD-16398 so I can see the programation of the Character ROM ?

2

I found the answer by experimenting. I am using the SerLCD fork from fourstix (for CircuitPython). To display characters with a value higher than 0xa0 (btw: the block 0x80 - 0x9f is not used) I call the function _put_char(), part of the class: Sparkfun_SerLCD. To display the ‘degrees sign’ I now call: lcd._put_char(0xdf).

See the image: https://imgur.com/JRsAT9G. Showing characters in the range 0xd0 and 0xfd

See the result with the ‘degrees sign’: https://imgur.com/Up6Qf0N.

Stay my second question about a datasheet of the SerLCD displays.