MK66 SDRAM databus lost

[danielrumary]

Hi I`m thinking of using the MK66FN2M0VLQ18 in a project and need to add SDRAM but I`m a bit confused as I cannot find any examples. It seems that Databus 0 - 15 is not available on FB_AD0-15 as it is used for the address lines - Do I need to use latches to multiplex the data bus with the address lines?

Any help would be greatly appreciated

[xiangjun_rong]

Hi,

i attach a doc, hope it can help you especially for initializing the SDRAM controller. But you need modify it based on the spec of SDRAM.

BR

Xiangjun Rong

[danielrumary]

Great Thanks Xiangjun

[xiangjun_rong]

Hi, Daniel,

Regarding your question, i am a bit confused, do you interface with SDRAM or SRAM? if you hook SDRAM, you have to use SDRAM SDR controller to connect, if you use SRAM/Nor flash, you can use FlexBus to connect.

If you use SDRAM, pls refer to the follwoing table in reference manual of K66.

Pls tell us the device even part number you want to hook.

BR

XiangJun Rong

[danielrumary]

Hi XiangJun

Thanks for your reply.

The SDRAM is MT48LC8M16A2P-75 (2 Meg x 16 x 4 Banks) - I have attached the pin mapping to what I think may work?

MK66 Pin (LQFP)	MK66 Pin Name	MK66 mode		MT48LC8M16A2P pin	MT48LC8M16A2P pin NAME
81	PTB0	SDRAM_CAS_b		17	SDRAM_CAS
82	PTB1	SDRAM_RAS_b		18	SDRAM_RAS
83	PTB2	SDRAM_WE		16	SDRAM_WE
84	PTB3	SDRAM_CS0_b		19	SDRAM_CS0
106	PTC3	CLKOUT		38	SDRAM_CLOCKOUT
125	PTC18	SDRAM_DQM1		39	SDRAM_DQM1
126	PTC19	SDRAM_DQM0		15	SDRAM_DQM0
136	PTD7	SDRAM_CKE		37	SDRAM_CKE
96	PTB17	FB_AD16/ SDRAM_D16		2	SDRAM_D0
95	PTB16	FB_AD17/ SDRAM_D17		4	SDRAM_D1
92	PTB11	FB_AD18/ SDRAM_D18		5	SDRAM_D2
91	PTB10	FB_AD19/ SDRAM_D19		7	SDRAM_D3
90	PTB9	FB_AD20/ SDRAM_D20		8	SDRAM_D4
89	PTB8	FB_AD21/ SDRAM_D21		10	SDRAM_D5
88	PTB7	FB_AD22/ SDRAM_D22		11	SDRAM_D6
87	PTB6	FB_AD23/ SDRAM_D23		13	SDRAM_D7
120	PTC15	FB_AD24/ SDRAM_D24		42	SDRAM_D8
119	PTC14	FB_AD25/ SDRAM_D25		44	SDRAM_D9
118	PTC13	FB_AD26/ SDRAM_D26		45	SDRAM_D10
117	PTC12	FB_AD27/ SDRAM_D27		47	SDRAM_D11
102	PTB23	FB_AD28/ SDRAM_D28		48	SDRAM_D12
101	PTB22	FB_AD29/ SDRAM_D29		50	SDRAM_D13
100	PTB21	FB_AD30/ SDRAM_D30		51	SDRAM_D14
99	PTB20	FB_AD31/ SDRAM_D31		53	SDRAM_D15
132	PTD5	FB_AD1/ SDRAM_A9		32	A7
131	PTD4	FB_AD2/ SDRAM_A10		31	A6
130	PTD3	FB_AD3/ SDRAM_A11		30	A5
129	PTD2	FB_AD4/ SDRAM_A12		29	A4
115	PTC10	FB_AD5/ SDRAM_A13		26	A3
114	PTC9	FB_AD6/ SDRAM_A14		25	A2
113	PTC8	FB_AD7/ SDRAM_A15		24	A1
112	PTC7	FB_AD8/ SDRAM_A16		23	A0
110	PTC5	FB_AD10/ SDRAM_A18		33	A8
109	PTC4	FB_AD11/ SDRAM_A19		34	A9
105	PTC2	FB_AD12/ SDRAM_A20		22	A10
104	PTC1	FB_AD13/ SDRAM_A21		35	A11
103	PTC0	FB_AD14/ SDRAM_A22		20	BANK SEL 0
97	PTB18	FB_AD15/ SDRAM_A23		21	BANK SEL 1

[stonos]

When using 16-bit wide SDRAM and D16-D31 on the MCU (mandatory from what I understand), is this realy correct:

125	PTC18	SDRAM_DQM1		39	SDRAM_DQM1
126	PTC19	SDRAM_DQM0		15	SDRAM_DQM0

I thought one should connect MCU DQM3 and DQM2 to SDRAM DQM1 and DQM0, or?

[danielrumary]

Yes I`m pretty sure its correct, I have to admit the datasheet is pretty poor at explaining how to wire SDRAM but the tables 35-4 to 13 are correct so you can blindly follow them. We invited a NXP technical expert to our business to double check for us and he confirmed that the above wiring is correct.  The Prototype boards are being made next week so I`ll be pretty disappointed if they don`t work. 

[stonos]

Hi Daniel,

I am working with K65, but the Reference manual looks the same. We are about to order a board any day. What I have been looking at is "Figure 35-2. Connections for External Memory Port Sizes" and from that figure my conclusion is that BS3 and BS2 shall be used with 16-bit wide memory (BS[3:0] is the DQM, see table 35-2). You can also check this thread on the same topic: https://community.nxp.com/thread/437787

[danielrumary]

Hi

I am so confused - I think you are right BS3 and BS2 should be used with 16bit SDRAM  but as it is memory mapped does it matter?

Bank select and DQM are two separate items.

Synchronous dynamic random-access memory - Wikipedia 

• DQM Data Mask. (The letter Q appears because, following digital logic conventions, the data lines are known as "DQ" lines.) When high, these signals suppress data I/O. When accompanying write data, the data is not actually written to the DRAM. When asserted high two cycles before a read cycle, the read data is not output from the chip. There is one DQM line per 8 bits on a x16 memory chip or DIMM.

• Bank Selection (BAn)[edit]

  SDRAM devices are internally divided into either 2, 4 or 8 independent internal data banks. One to three Bank Address inputs (BA0, BA1 and BA2) are used to select which bank a command is directed toward.

I`m pretty sure that you can wire the bank select lines straight to the next available address lines. 

[stonos]

When checking table 35-2 BS[3:0] should be interpret as "Byte Select" and not "Bank Selection":

"SDRAM byte selects BS[3:0] function as byte enables to the SDRAMs. They connect to the DQM signals (or data qualifier masks) of the SDRAMs.".

In Figure 35-2 the BS signals have the text "Byte Enable" to the left of them to make it more confusing.

A problem is that NXP uses BS instead of DQM in the Reference manual and DQM in the Datasheet not BS.

I am still not 100% sure what is right, but I whould really like be 100% sure before we order our board...

[danielrumary]

This is ridiculous - why is the datasheet so confusing?

I am going to contact NXP directly and get them to advise, once done I will let you know on this post.

Best Regards Dan.

[danielrumary]

Hi I have contact NXP and they kindly reviewed the design for me, it looks like the design was wrong and that the DQM signals need to connect to DQM2 and DQM3.

Also just to clarify the Bank address lines are correct:

In terms of the Bank Address lines, on the SDR these select one of the 4 internal banks. To make the memory space mapped to the K66 contiguous, we use the next 2 address lines. So I’m happy with using SDRAM_A22 and SDRAM_A23 connected to BANK_SEL0 and BANK_SEL1. That is consistent with both the TWR schematic and the Table 35-16 example in the device reference manual (pdf page 900) of Rev2 reference manual.

So with reasonable confidence below is how you connect 128Mbit of SDRAM to the MK66 in 16bit mode, although we will only 100% know once we have re-spun the PCB.

Connecting MT48LC8M16A2P to MK66FN2M0VLQ18.

MK66 Pin (LQFP)	MK66 Pin Name	MK66 mode		MT48LC8M16A2P pin	MT48LC8M16A2P pin NAME
81	PTB0	SDRAM_CAS_b		17	SDRAM_CAS
82	PTB1	SDRAM_RAS_b		18	SDRAM_RAS
83	PTB2	SDRAM_WE		16	SDRAM_WE
84	PTB3	SDRAM_CS0_b		19	SDRAM_CS0
106	PTC3	CLKOUT		38	SDRAM_CLOCKOUT
124	PTC17	SDRAM_DQM3		39	SDRAM_DQMU
123	PTC16	SDRAM_DQM2		15	SDRAM_DQML
136	PTD7	SDRAM_CKE		37	SDRAM_CKE
96	PTB17	FB_AD16/ SDRAM_D16		2	SDRAM_D0
95	PTB16	FB_AD17/ SDRAM_D17		4	SDRAM_D1
92	PTB11	FB_AD18/ SDRAM_D18		5	SDRAM_D2
91	PTB10	FB_AD19/ SDRAM_D19		7	SDRAM_D3
90	PTB9	FB_AD20/ SDRAM_D20		8	SDRAM_D4
89	PTB8	FB_AD21/ SDRAM_D21		10	SDRAM_D5
88	PTB7	FB_AD22/ SDRAM_D22		11	SDRAM_D6
87	PTB6	FB_AD23/ SDRAM_D23		13	SDRAM_D7
120	PTC15	FB_AD24/ SDRAM_D24		42	SDRAM_D8
119	PTC14	FB_AD25/ SDRAM_D25		44	SDRAM_D9
118	PTC13	FB_AD26/ SDRAM_D26		45	SDRAM_D10
117	PTC12	FB_AD27/ SDRAM_D27		47	SDRAM_D11
102	PTB23	FB_AD28/ SDRAM_D28		48	SDRAM_D12
101	PTB22	FB_AD29/ SDRAM_D29		50	SDRAM_D13
100	PTB21	FB_AD30/ SDRAM_D30		51	SDRAM_D14
99	PTB20	FB_AD31/ SDRAM_D31		53	SDRAM_D15
132	PTD5	FB_AD1/ SDRAM_A9		32	A7
131	PTD4	FB_AD2/ SDRAM_A10		31	A6
130	PTD3	FB_AD3/ SDRAM_A11		30	A5
129	PTD2	FB_AD4/ SDRAM_A12		29	A4
115	PTC10	FB_AD5/ SDRAM_A13		26	A3
114	PTC9	FB_AD6/ SDRAM_A14		25	A2
113	PTC8	FB_AD7/ SDRAM_A15		24	A1
112	PTC7	FB_AD8/ SDRAM_A16		23	A0
110	PTC5	FB_AD10/ SDRAM_A18		33	A8
109	PTC4	FB_AD11/ SDRAM_A19		34	A9
105	PTC2	FB_AD12/ SDRAM_A20		22	A10
104	PTC1	FB_AD13/ SDRAM_A21		35	A11
103	PTC0	FB_AD14/ SDRAM_A22		20	BANK SEL 0
97	PTB18	FB_AD15/ SDRAM_A23		21	BANK SEL 1

Regards Dan.

[coyote47]

Hi Daniel, 

Any update to how the above pinout worked?

Thanks,

Ryan

[xiangjun_rong · Accepted solution]

Hi,

I have checked the data sheet of MT48LC8M16A2 – 2 Meg x 16 x 4 Banks, this is the parameters:

row addressing:4K A[11:0]

column addressing:512 A[8:0]

bank addressing:4 BA[1:0]

You have to use the Table 35-8. SDRAM Controller to SDRAM Interface (16-Bit Port, 9-Column Address Lines) in RM of K66, the data bus is hooked to the High half word, I think your connection is okay. but I do not check the pin assignment.

BR

Xiangjun Rong

[danielrumary]

Thanks Xiangjun

Just one more clarification:

Do I wire the bank select lines to the upper address lines?

i.e.

BANK_SEL_0 = SDRAM_A22

BANK_SEL_1 = SDRAM_A23

Best Regards Dan.

[xiangjun_rong]

Hi,

For K66, you can locate the SDRAM to the address space:

0x8000_0000–0x8FFF_FFFF SDRAM (External RAM - Write-through) All masters

in other words, your SRDAM space will be:

0x8000 0000 to 0x80FF FFFF for MT48LC8M16A2

But you have to initialize the SDRAM controller before you access the SDRAM.

I attach an doc, hope it can help you.

BR

XiangJun Rong