Ich habe hier ein ATxMEGA128A1 mit 512kB-SRAM.
Den HEAP habe ich auf 0x4000-0xFFFF verschoben (-D__heap_start=0x804000
-D__heap_end=0x80ffff)
Die Abfrage des Speichers zeigt aber immer 0 Bytes frei an. Warum?
Interface für externen Speicher aktivieren:
1 | void __attribute__ ((naked, section(".init3"))) init_xram (void)
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2 | {
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3 | PORTH_OUT = 0xF3; // enable pullups
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4 | PORTH_DIR = 0xFF; // set port H to output - control & address
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5 | PORTK_DIR = 0xFF; // set port K to output - address lines
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6 |
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7 | /* 3 Port Mode, SRAM 8-Bit ALE 1+2 */
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8 | EBI_CTRL = EBI_SDDATAW_8BIT_gc | EBI_LPCMODE_ALE1_gc | EBI_SRMODE_ALE12_gc | EBI_IFMODE_3PORT_gc;
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9 | /* SRAM Mode, 512kB */
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10 | EBI_CS2_CTRLA = EBI_CS_ASIZE_512KB_gc | EBI_CS_MODE_SRAM_gc;
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11 | /* SRAM IS61LV5128AL 512K x 8 10ns */
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12 | EBI_CS2_CTRLB = EBI_CS_SRWS_2CLK_gc;
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13 | /* SRAM Start Adresse ( 512kB belegt : 0x00004000 - 0x0007FFFF ) */
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14 | EBI_CS2_BASEADDR = 0x0000;
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15 |
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16 | EBI_CS0_CTRLA = EBI_CS_MODE_DISABLED_gc;
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17 | EBI_CS1_CTRLA= EBI_CS_MODE_DISABLED_gc;
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18 | EBI_CS3_CTRLA= EBI_CS_MODE_DISABLED_gc;
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19 | }
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Speicher initialisieren (wird mit 0xAA gefüllt):
1 | // !!! Never call this function, it is part of .init-Code
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2 | void __attribute__ ((naked, used, section(".init8"))) init_mem (void);
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3 | void init_mem (void)
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4 | {
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5 | // Use inline assembler so it works even with optimization turned off
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6 | __asm volatile (
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7 | "ldi r30, lo8 (__heap_start)" "\n\t"
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8 | "ldi r31, hi8 (__heap_start)" "\n\t"
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9 | "ldi r24, %0" "\n\t"
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10 | "ldi r25, hi8 (%1)" "\n"
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11 | "0:" "\n\t"
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12 | "st Z+, r24" "\n\t"
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13 | "cpi r30, lo8 (%1)" "\n\t"
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14 | "cpc r31, r25" "\n\t"
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15 | "brlo 0b"
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16 | :
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17 | : "i" (MASK), "i" (__heap_end+1)
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18 | );
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19 | }
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Freien Speicher anzeigen:
1 | // Get minimum of free memory (in bytes) up to now.
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2 | unsigned short get_mem_unused (void)
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3 | {
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4 | unsigned short unused = 0;
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5 | unsigned char *p = __heap_start;
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6 |
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7 | do
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8 | {
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9 | if (*p++ != MASK)
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10 | break;
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11 |
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12 | unused++;
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13 | } while (p <= (unsigned char*) __heap_end);
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14 |
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15 | return unused;
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16 | }
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malloc-x2.png
(2,9 KB)
