In the specifications it is indicated that this module can work up to 70ºc but from 50ºc the contrast is severely affected and it is necessary to modify the contrast using the "SC" command. Due to this I am in need of implementing functions that constantly monitoring the temperature of the lcd and make compensating contrast adjustments. I have been watching the command "RDTMP" (Read Chip Temperature) but I can not get it to work. When I send "RDTMP" to the module, it does not return anything at all through the tx pin. ("CLK" in Usart Mode)

The software version is v4.1B What do you recommend?.

 The temperature function only available on the display module with touch screen, it use the touch screen controller to achive it.