How to assign CLKBLK to port in ASM?

[ffomich]

Hi,
can anyone help me with assembler?

There is working example from SpdifReceive.S

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void task(in port p, //r0
              clock clk); //r1


    SETCI   r1, 7   // XS1_SETC_RUNR_STOP - stop clock
    SETCLK  r0, r1 - assign clock to port
    SETCI   r1, 15  // XS1_SETC_RUNR_START - start clock

Each CLKBLK has unique code

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#define XS1_CLKBLK_REF 0x6
#define XS1_CLKBLK_1 0x106
#define XS1_CLKBLK_2 0x206
#define XS1_CLKBLK_3 0x306
#define XS1_CLKBLK_4 0x406
#define XS1_CLKBLK_5 0x506

How can I assign port to another CLKBLK inside my task using CLKBLK code?
Something like this:

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void task(in port p, //r0
              clock clk); //r1

    SETCI   r1, 7   // stop clock
    LDC	r4, 0x0106 // load CLKBLK code
    SETCLK  r0, r4 // assign new clock to port
    SETCI   r4, 15 // start clock

[larry]

I find that often I don't actually need to configure ports and clock blocks in assembly. Doing it is tedious, cumbersome and error prone. Instead I now try to configure my ports and clock blocks in XC outside of my assembly routines.

If you absolutely can't avoid assembly for port/clock block configuration, however, use the SETCLK instruction. Remember to stop the clock block, as you did in your example. Are you having any issues with this code?

It might be useful to write a little test program using the XC configure functions and look in simulator output to see SETCLK/SETC instructions those configure functions compiled into.

[ffomich]

Now it work. I don't know why it didn't work before :)

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r0 - port, r2 - divider, r4 - clock

    LDC   r4, XS1_CLKBLK_1 // load CLKBLK code
    SETCI   r4, 7   // stop clock
    SETD   r4, r2  // set clock divider  
    SETCLK  r0, r4 // assign new clock to port
    SETCI   r4, 15 // start clock

Note:

xCORE-200: The XMOS XS2 Architecture, p.191
Format of SETCLK instruction is:

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SETCLK port, clock

XS1 PORTS: USE AND SPECIFICATION (1.02) 2008/11/25, ch.3.6
All examples have inverse parameters order.