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Support on Nor Flash in page mode through GPMC from AM335x
Hi team,
One of my customers is using AM335x. They wonder to know whether Nor Flash is supported in page mode through GPMC in AM335x. If yes, could you please kindly suggest which registers should be configured and what is the value? Thanks a lot for your help in advance.
YES, My hardware is using non-multiplexed mode burst NOR flash device. I have write the GPMC_CONFIG1_i with 0x41401010 instead 0x00401010 ,other GPMC_CONFIG2-7 is using the CPU default value with boot. But that is nothing happened with the read speed.
Can you give me a standard register configuration?
There is no standard register configuration. All 7 registers need to be configured according to your external device required timings. Look in section 7.1.4.2 of the TRM.
Of course. The flash is PC28F512M29EWL.
The u-boot command to configure the timging is like this:
//new page timing
mw 0x50000060 41001000;mw 0x50000064 00090D00;mw 0x50000068 00020201;mw 0x5000006C 08020D01;mw 0x50000070 030C090D;mw 0x50000074 09030100;;mw 0x50000078 00000c48
I have checked the singal read with an oscilloscope. But the speed of page read is still not ok. Any other suggestions?
Can you telle me the difference between singel read and page read? I think the only difference is "GPMC_CONFIG1.READMULTIPLE = 1, ATTACHEDDEVICEPAGELENGTH = 2h(16 word), GPMC_CONFIG5_i.PAGEBURSTACCESSTIME = 3(3 gpmc_clk, 30 ns)".
Thanks a lot.
My problem is only that 16 words page read has not been displayed in Oscilloscope.
Now have new progress：
1. u-boot cmd: md.w 0x08000000 0x10, the read access is single;
2. u-boot cmd: md.l 0x08000000 0x10, the read access is 2 words page;
3. I use one assembly function like this:
void static asm_mem_read(register unsigned long addr, unsigned int size)
{
register unsigned int end = size;
asm volatile(
"loop_read: ldmia %0!,{r0-r7}\n"
" sub %1, %1, #32\n"
" cmp %1, #0\n"
" bgt loop_read\n"
: /* no outputs */
: "r" (addr), "r" (end)
: "memory", "r0", "r1", "r2", "r3", "r4","r5","r6","r7");
}
The read access is only 4 words page; why is it not 8 words page read?
Hi Biser/all,
Can you tell me that whether gpmc can support 16 words page read(Asynchronous mode)?
I worry about gpmc bus can not support this fearture.
Thanks a lot.
Lusheng Zhang
