Sdram Controller; Sdram Controller Main Features; Sdram External Memory Interface Signals; Table 79. Sdram Signals - ST STM32F446 Series Reference Manual

Flexible memory controller (FMC)
11.7

SDRAM controller

11.7.1

SDRAM controller main features

The main features of the SDRAM controller are the following:
•
Two SDRAM banks with independent configuration
•
8-bit, 16-bit data bus width
•
13-bits Address Row, 11-bits Address Column, 4 internal banks: 4x16Mx16bit
(128 MB), 4x16Mx8bit (64 MB)
•
Word, half-word, byte access
•
SDRAM clock can be HCLK/2 or HCLK/3
•
Automatic row and bank boundary management
•
Multibank ping-pong access
•
Programmable timing parameters
•
Automatic Refresh operation with programmable Refresh rate
•
Self-refresh mode
•
Power-down mode
•
SDRAM power-up initialization by software
•
CAS latency of 1,2,3
•
Cacheable Read FIFO with depth of 6 lines x32-bit (6 x14-bit address tag)
11.7.2

SDRAM External memory interface signals

At startup, the SDRAM I/O pins used to interface the FMC SDRAM controller with the
external SDRAM devices must configured by the user application. The SDRAM controller
I/O pins which are not used by the application, can be used for other purposes.
SDRAM signal
SDCLK
SDCKE[1:0]
SDNE[1:0]
A[12:0]
D[15:0]
BA[1:0]
NRAS
NCAS
SDNWE
NBL[1:0]
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Table 79. SDRAM signals

I/O
Description
type
O SDRAM clock
SDCKE0: SDRAM Bank 1 Clock Enable
O
SDCKE1: SDRAM Bank 2 Clock Enable
SDNE0: SDRAM Bank 1 Chip Enable
O
SDNE1: SDRAM Bank 2 Chip Enable
O
I/O Bidirectional data bus
O Bank Address
O Row Address Strobe
O Column Address Strobe
O Write Enable
Output Byte Mask for write accesses
O
(memory signal name: DQM[1:0]
RM0390 Rev 4
Address
RM0390
Alternate function
-
-
-
FMC_A[12:0]
FMC_D[15:0]
FMC_A[15:14]
-
-
-
FMC_NBL[1:0]