STMF7 (100 LQPF) Missing LCD pins

[stuart239955_st]

Posted on October 09, 2015 at 11:18

Hi,

Im currently evaluating which STM32F7 controller for use in a HMI project.

I was studying the connections required for the 24bit LCD interface on the STM32F746VG (100 LQFP). Looking at the GPIO alternate function mapping tables in the data sheet I cant find connections for LCD_R0 or LCD_B1 on the 100 LQFP variants.

I also found 2 instances of LCD_R4 on pins PA11 and PA5.

This has left me a little confused. Any help would be greatly appreciated.

Thanks

Stuart

[waclawek.jan]

Posted on October 09, 2015 at 13:09

Accept it as a fact.

Pins placement/assignment to AFs is a matter of tradeoff - increasing number of AFs per pin and increasing number of pins per AF both increase silicon area. ST also tries hard to maintain pin compatibility - OK the QFP100 is layout-incompatible (due to one whole side is shifted by one pin to make space for an extra supply pin), but still the port.pin-to-AF scheme is largely compatible across the whole STM32 family.

JW

[e1369008]

Posted on October 09, 2015 at 13:19

So, nothing to worry, when using 18-bit mode, you have R2-R7, G2-G7, B2-B7 (6+6+6=18), when using 16-bit mode, you must use R3-R7, G2-G7, R3-R7 (5+6+5=16).

[stuart239955_st]

Posted on October 12, 2015 at 11:43

Hi, thanks for the information.

So are you suggesting the 100 LQFP's cant do 24bit?

[qwer.asdf]

Posted on October 12, 2015 at 14:38

> So are you suggesting the 100 LQFP's cant do 24bit?

Yes, it seems so, you have to get a bigger than 100pin part to use 24bit LTDC.