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Hi,
I trying to build the peripheral around Cortex-M0 IP core thorugh AHB-lite system. Right now I have to integrate Cortex-M0 with the DDR2 SRAM (1Gb) through AHB lite.
I searched on internet which shows interfacing only through core generator (MIG). Is there a way I can use Xilinx core generator to interface through AHB lite system.
I am using Atlys Xilinx Spartan 6.
I also have some example SoC design which interface 128Mb SRAM to Cortex-M0 though AHB lite for Nexsys 3 board . But the Board I am using has DDR2 RAM.
Thanks
I still could not figure out what this does and LED is still all ZERO.
In this waveform, the reset get activated every couple of clock cycles. It seem the reset generation in your test bench has some problem.
Sent from my iPad
Actually tried with all reset value Low and High also toggling. But LED signal remain zero all time. If you see here RESETn =1 it is disabled. and for RESETn=0 it gives only the first value of hex file. As the code suggest it should it should toggle b/w 55 and AA?? Please correct me if I am wrong
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Please see o/p for both resetn high and low.
The reset is an active low signal. So it should start with 0 (active), and then switch to 1 (de-assert) after.
The software code in you previous message need an addition branch to jump back to the beginning, and you also need to add a vector table in the program image.
Still All zero and also at 202.3us it becomes 1000000. But I could not see the AA or 55 pattern on LED.
The Cortex-M series treat the 32-bit values at 0x0 and 0x4 as the initial stack pointer and reset vector. At present the CPU is interpreting the first four instructions as these values (0x4906, 0x4807, 0x6008, 0x4807), and is thus branching off to uninitialised memory. You need to add a vector table containing at least the initial stack pointer value and the location of the code to run at reset; as a minimum this might look like:
DCD stack DCD start start LDR r1,=0x50000000 LDR r0,=0x55 STR r0,[r1] LDR r0,=0x2FFFFF Loop SUBS r0,r0,#1 BNE Loop LDR r1,=0x50000000 LDR r0,=0xAA STR r0,[r1] LDR r0,=0x2FFFFF Loop1 SUBS r0,r0,#1 BNE Loop1 B start ALIGN LTORG ALIGN SPACE 64 stack
hth
Simon.
I did it this way. is it correct. The code you have given is giviing error as A1163E: Unknown opcode stack , expecting opcode or Macro
This should be fine as long as __Vectors is being treated as constant data/text and is being linked at the beginning of the final image, i.e. it is ending up at address zero.
I run the above code on cortex m0 and stimulated on LSIM but could not see 0x55 and 0xAA pattern. above stimulation result is actually for the hex code generated from this asm file
For simulation purpose you might want to reduce the initial loop counter value to a smaller size like 20.
I have changed count value as well to 20(14hex). But still i think it is branching to uninitialized memory location. I am also sending you the memory initialized after hex file generation. Still I could not see the pattern on data bus. checked in disassembly window putting break point after each line it is working but on on LSIM. I do not know the reason
Your image still starts with the two LDR instructions, you need to ensure that the first two values are the stack pointer and reset vector values. Try moving the two DCDs you have in to the area you have defined as CODE, i.e. just before the first LDR.
Please also reuse the example software project from the EDK. (Assume you are using MDK)
As Simon said the vector table is missing from your program image.
The example project setup with your program code (unused vectors removed, loop counter reduced to 20) in EDK should generate a hex file code.hex,
which should contains something like:
000003FC <= initial Main SP value
00000009 <= Reset handler starting address (LSB set to 1 for Thumb state)
48074906 <= Reset handler first instruction at 0x8
48076008
D1FD1E40
48064903
48046008
0000E7F2
00000014
00000055
002FFFFF
000000AA
Thanks a lot. I got it working on board.
1) Where can I find Example project from the EDK?
2) For writing software code which should we prefer assembly or embedded C?
3) I have to write a filtering code and feature extraction for the same signal. I guess C would be more convenient.
4) I thought of interfacing a Add on adc to my board which connect to board through I2C. Which I think require a AHB to I2C controller
http://in.element14.com/digilent/pmodad2/ad7991-4x12bit-adc-pmod/dp/2290115
5) If I add UART to cortex M0. How do I verify that it is working fine.
You can find example project in the EDK you downloaded in sub directories like
CM0DS-DesignKit\EXAMPLE_SoC\ARMSOC_1\Software
The Keil MDK projects has file extension of .vproj
For write software code it is much more common to use C. The EDK is designed for students who are interested in low level details, that's why the examples are in assembly language.
The EDK provide example UART in one of the directories:
CM0DS-DesignKit\AHB_Peripherals\AHBL_UART
However, there is no I2C module, you have to design your own.
regards,
Joseph