[rtems commit] bsp/lpc24xx: Add SDRAM mode settings comment

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    6cad529ccb160ee6cc5991e0fb52c5a8ce2f027f
Changeset: http://git.rtems.org/rtems/commit/?id=6cad529ccb160ee6cc5991e0fb52c5a8ce2f027f

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Thu May  9 09:16:20 2019 +0200

bsp/lpc24xx: Add SDRAM mode settings comment

---

 bsps/arm/lpc24xx/start/start-config-emc-dynamic.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/bsps/arm/lpc24xx/start/start-config-emc-dynamic.c b/bsps/arm/lpc24xx/start/start-config-emc-dynamic.c
index 801b33f..fe25af2 100644
--- a/bsps/arm/lpc24xx/start/start-config-emc-dynamic.c
+++ b/bsps/arm/lpc24xx/start/start-config-emc-dynamic.c
@@ -232,6 +232,15 @@ BSP_START_DATA_SECTION const lpc24xx_emc_dynamic_config
 #endif
 };
 
+/*
+ * Mode shift is determined for RBC by:
+ *
+ *   bus width in bits / 16 + bank bits + column bits
+ *
+ * Mode shift is determined for BRC by:
+ *
+ *   bus width in bits / 16 + column bits
+ */
 BSP_START_DATA_SECTION const lpc24xx_emc_dynamic_chip_config
   lpc24xx_start_config_emc_dynamic_chip [] = {
 #if defined(LPC24XX_EMC_MT48LC4M16A2)
@@ -240,7 +249,7 @@ BSP_START_DATA_SECTION const lpc24xx_emc_dynamic_chip_config
 
     /*
      * Use SDRAM, 0 0 001 01 address mapping, disabled buffer, unprotected
-     * writes.  4 banks, 12 row lines, 8 column lines.
+     * writes.  4 banks, 12 row lines, 8 column lines, RBC.
      */
     .config = 0x280,