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stm32F4: LTDC - bit defines without semantics

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The LTDC include file was defined with combined bit
semantics and bit position. As a result instead of
LTDC_GCR_VSPOL which is the bit which defines vertical
sync polarity, this had been defined to be
LTDC_GCR_VSPOL_LOW (0) and LTDC_GCR_VSPOL_HIGH (non zero).
This sort of define makes it impossible to know ahead of
time what operation would set or reset the bit (some are
negative logic, others are postive logic, so affirmative
defines could mean either "set the bit" or "reset the bit"
I've added the non-semantic bit define so that it is clear
in my code if the bit is being set or reset.

Discussion took place at https://github.com/libopencm3/libopencm3/pull/889
This commit is contained in:
Chuck McManis 2018-03-02 11:26:29 -08:00 committed by Karl Palsson
parent 034dbf20ff
commit 1e9a2e641c
1 changed files with 8 additions and 0 deletions
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8
include/libopencm3/stm32/f4/ltdc.h
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@ -153,6 +153,14 @@
#define LTDC_GCR_HSPOL_ACTIVE_LOW (0<<31)
#define LTDC_GCR_HSPOL_ACTIVE_HIGH (1<<31)
/* GCR - register bit defines (no semantics) */
#define LTDC_GCR_HSPOL (1 << 31)
#define LTDC_GCR_VSPOL (1 << 30)
#define LTDC_GCR_DEPOL (1 << 29)
#define LTDC_GCR_PCPOL (1 << 28)
#define LTDC_GCR_DITHER (1 << 16)
#define LTDC_GCR_LTDCEN (1 << 0)
/* --- LTDC_SRCR values ---------------------------------------------------- */
/* Vertical Blanking Reload */