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Architecture
394
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
DDR2/mDDR Memory Controller
Table 14-14. Mobile DDR SDRAM Configuration by EMRS(1) Command
Memory
Controller
Address Bus
Value
mDDR SDRAM
Register Bit
mDDR SDRAM Field
Function Selection
DDR_A[11:7]
0
11:7
Operating Mode
Normal operating mode
DDR_A[6:5]
DDRDRIVE[1:0]
6:5
Output Driver Impedance
Value of 0, 1, 2, or 3 is programmed based
on value of DDRDRIVE[1:0] bits in SDRAM
configuration register (SDCR).
DDR_A[4:3]
0
4:3
Temperature Compensated
Self Refresh
Value of 0
DDR_A[2:0]
PASR bits
2:0
Partial Array Self Refresh
Value of 0, 1, 2, 5, or 6 is programmed based
on value of PASR bits in SDRAM
configuration register 2 (SDCR2).
14.2.13.1 Initializing Following Device Power Up or Reset
Following device power up or reset, the DDR2/mDDR memory controller is held in reset with the internal
clocks to the module gated off. Before releasing the DDR2/mDDR memory controller from reset, the
clocks to the module must be turned on. Perform the following steps when turning the clocks on and
initializing the module:
1. Program PLLC1 registers to start the PLL1_SYSCLK1 (that drives 2X_CLK). For information on
programming PLLC1, see the
Phase-Locked Loop Controller (PLLC)
chapter.
2. Program Power and Sleep Controller (PSC) to enable the DDR2/mDDR memory controller clock.
3. Perform VTP IO calibration:
(a) Clear POWERDN bit in the VTP IO control register (VTPIO_CTL).
(b) Clear LOCK bit in VTPIO_CTL.
(c) Pulse CLKRZ bit in VTPIO_CTL:
(i) Set CLKRZ bit and wait at least 1 VTP clock cycle (clock cycle wait can be achieved by
performing a read-modify-write of VTPIO_CTL in the next step).
(ii) Clear CLKRZ bit and wait at least 1 VTP clock cycle (clock cycle wait can be achieved by
performing a read-modify-write of VTPIO_CTL in the next step).
(iii) Set CLKRZ bit.
(d) Poll READY bit in VTPIO_CTL until it changes to 1.
(e) Set LOCK bit in VTPIO_CTL. VTP is locked and dynamic calibration is disabled.
(f) Set POWERDN bit in VTPIO_CTL to save power.
4. Set IOPWRDN bit in VTPIO_CTL to allow the input receivers to save power when the PWRDNEN bit in
the DDR PHY control register 1 (DRPYC1R) is set.
5. Configure DRPYC1R. All of the following steps may be done with a single register write to DRPYC1R:
(a) Set EXT_STRBEN bit to select external DQS strobe gating.
(b) Set PWRDNEN bit to allow the input receivers to power down when they are idle.
(c) Program RL bit value to meet the memory data sheet specification.
6. Configure the DDR slew register (DDR_SLEW):
(a) For DDR2, clear DDR_PDENA and CMOSEN bits.
(b) For mDDR, set the DDR_PDENA and CMOSEN bits.
7. Set the BOOTUNLOCK bit (unlocked) in the SDRAM configuration register (SDCR).
8. Program SDCR to the desired value with BOOTUNLOCK bit cleared to 0 and TIMUNLOCK bit set to 1
(unlocked).
9. For mDDR only, program the SDRAM configuration register 2 (SDCR2) to the desired value.
10. Program the SDRAM timing register 1 (SDTIMR1) and SDRAM timing register 2 (SDTIMR2) to the
desired values to meet the memory data sheet specification.
11. Clear TIMUNLOCK bit (locked) in SDCR.